Transcriber’s Note:

The cover image was created by the transcriber and is placed in the public domain.

ON
CHLOROFORM
AND
OTHER ANÆSTHETICS:
THEIR
ACTION AND ADMINISTRATION.

BY

JOHN SNOW, M.D.

LICENTIATE OF THE ROYAL COLLEGE OF PHYSICIANS.

EDITED,

WITH A MEMOIR OF THE AUTHOR,

BY

BENJAMIN W. RICHARDSON, M.D.,

LICENTIATE OF THE ROYAL COLLEGE OF PHYSICIANS.

LONDON:

JOHN CHURCHILL, NEW BURLINGTON STREET.

MDCCCLVIII.

PREFACE.

The book here presented to the reader is the legacy to science of Dr. John Snow. The completion of the work was his last act and deed. In editing the book, therefore, all that remained to be done consisted in the construction of the index, and in this a plan suggested by the author himself has been followed.

In contributing the memoir, I have performed a painful and unexpected duty: the fulfilment of a promise given at a moment when two friends who often enjoyed close companionship met at one of their happiest meetings. The promise was given with the idea of fulfilment far distant, or improbable altogether, and, as connected with a more extended biographical survey, reserved for the work of years long in the future; it is called for now hastily and in deep sorrow.

Writing with the fact of my late friend’s death not as yet fully realized; with the sensation still on me at intervals (like one who has lost a part of his own body, and yet at times conceives the lost present), that he cannot possibly be so far away; I may, perchance be pardoned for any deficiencies in style or matter. I have done my best, and leave it so.

B. W. RICHARDSON.

12, Hinde Street, Manchester Square.

August 6th, 1858.

CONTENTS.

THE
LIFE OF JOHN SNOW, M.D.

There is not much credit in the mere acts of living and dying; in being driven by unavoidable fate through the common journey, with shoulders uncovered and the whip over them; in doing nothing save the drudgery of existence; in enjoying, in an approach to the recognition of enjoyment, the brief dreams of childhood; in struggling into manhood; in battling through the after-strife obedient to the castigator behind; and in dying at last, as though life had never been; dead to-day, wept for tomorrow, and forgotten by the morrow’s succeeding sun. There is not much credit in this surely, for credit must be earned by something done beyond that which all must perforce do. But, in the face of all the struggles incidental to the existence, so to have managed as to have stolen out of time hours which other men knew not in their calendar—so to have defied the inexorable taskmaster as to perform more than is included in his demands; so to have willed and acted as to live on when death has done his worst; to assist all coming wayfarers in their conflict wherever they may meet it; to prove that there is something more in life than labour lost, and nothing more in death than an idea—Hoc opus hic labor est—in this there is achieved the grand attainment; the perpetual life.

He whom I, with poor biographer’s pencil, put forward now in brief sketch, is one amongst the few who have thus realized the ideality of death. It were but little matter, therefore, though no biography should appear at all; it is of but little count that such biography, as the recollections of friends and intimates shall call forth, be scanty in its details; it is of but little count that the life of him who is to be shadowed forth is destitute of incident fitted for the taste of wonder-loving, passion-courting, romance-devouring, readers. Biographies for these are common. Good men are scarce.

John Snow, the subject of the present memoir, was born at York, on the fifteenth day of June, 1813. He was the eldest son of his parents. His father was a farmer. His mother, who is living, resides still at York. As a child, he showed his love of industry; and increasing years added only to the intensity with which he applied himself to any work that was before him. He occasionally assisted his father in agricultural pursuits, and often in later life spoke with great naïveté of the recollections of those early winter mornings when his boy’s fingers were too intimately to be pleasantly acquainted with the effects of benumbing cold. He was first sent to a private school at York, where he learned all that he could learn there. He was fond of the study of mathematics, and in arithmetic became very proficient. At the age of fourteen, he went to Newcastle-on-Tyne, as an apprentice to Mr. William Hardcastle, surgeon, of that place. He had also the opportunities of studying at the Newcastle Infirmary. During the third year of his apprenticeship, viz., when he was seventeen years old, he formed an idea that the vegetarian body-feeding faith was the true and the old; and with that consistency which throughout life attended him, tried the system rigidly for more than eight years. He was a noted swimmer at this time, and could make head against the tide longer than any of his omnivorous friends. I have heard him tell that so long as he continued to qualify his vegetables with milk and butter, the vegetarian plan supported him fairly. But on one unfortunate morning, when taking his milk breakfast, some quizzical friend, learned in botany, cross-examined him as to the vegetable on which he was then feeding. The joke went home; and the use of milk, as food for a pure vegetarian, became too absurd for consistency. The milk, therefore, must be put aside, and the butter and the eggs. The experiment did not answer; the health of our pure vegetarian gave way under the ordeal, and although in after life he maintained that an approach to the vegetarian practice was commendable, in that it kept the body in better tone for the exercise of the mind, he admitted that in his own case his health paid the forfeit of his extreme adherence to an hypothesis. Amongst his earlier scientific readings was a book in defence of the vegetable regimen by John Frank Newton. This book is annotated by himself, 1833. It is an useful book, full of curious arguments, facts and suggestions, many of which, as his own after writings indicate, he had carefully studied and applied.

At or about the same time that he adopted his vegetarian views, he also took the extremity of view and of action, in reference to the temperance cause. He not only joined the ranks of the total abstinence reformers, but became a powerful advocate of their principles for many succeeding years. In the latter part of his life, he occasionally and by necessity took a little wine, but his views on the subject remained to the end unchanged; he had strong faith in the temperance cause, and a belief that it must ultimately become an universal system.

In 1831–32, cholera visited Newcastle and its neighbourhood, and proved terribly fatal. In the emergency, Mr. Snow was sent by Mr. Hardcastle to the Killingworth Colliery, to attend the sufferers from the disease there. In this labour he was indefatigable, and his exertions were crowned with great success. He made also on this occasion many observations relating to this disease, which proved to him of immense account in after years.

He left Newcastle in 1833, and engaged himself as assistant to Mr. Watson of Burnop Field, near Newcastle. Here he resided for twelve months, fulfilling the assistant duties; regarding which it can only be said, and that from analogy, that they were neither without their anxiety nor their reward. Leaving Burnop Field in 1834–5, he revisited his native place, York; made a short stay, and thence, to a certain half-inaccessible village called Pately Bridge, in Yorkshire, to assistant it with Mr. Warburton, surgeon there. Some few years ago a friend of mine went to the same village, by the recommendation of Dr. Snow, as assistant to the present Mr. Warburton of that place, a son of Dr. Snow’s “old master”. The circumstance of this recommendation often led Dr. Snow to refer to his life at Pately Bridge in our conversations. He invariably, on such occasions, spoke of Mr. Warburton, his “old master”, in terms of sincere respect, and depicted his own life there with great liveliness. He was a vegetarian then, and his habits puzzled the housewives, shocked the cooks, and astonished the children. His culinary peculiarities were, however, attended to with great kindliness. Eighteen months at Pately Bridge, with many rough rides, a fair share of night work, a good gleaning of experience, and this sojourn was over. Now back again went our student to York, to stay this time a few months, and—not to be idle—to take an active share in the formation of temperance societies. In leisure days during this period it was his grand amusement to make long walking explorations into the country. In these peregrinations he collected all kinds of information, geological, social, sanitary, and architectural.

At last York must be again left; the London student life was in view. In the summer of the year at which we have arrived, 1836, he set off from York to Liverpool, and, trudging it afoot from Liverpool through the whole of North and South Wales, turned London-ward, calling at Bath by the way, on a visit to his uncle, Mr. Empson, to whom, to the end of his life, he was devotedly attached. October 1836—eventful October—brought him to the “great city”, and placed him on the benches of the Hunterian School of Medicine in Windmill-street: a school long since closed, and now almost a myth; like the mill which gave the name to the locality.

I am indebted to the courtesy of Mr. Joshua Parsons of Beckington, near Bath, for an insight into the life and manners of my beloved friend during his student career. Mr. Parsons had the happiness to be the special fellow-student of Snow. Their friendship, cemented early in life, never declined, but had added to it, “on my part,” says Mr. Parsons, “respect and admiration for the solid talents and industry of my old colleague.” Speaking of their common labours, Mr. Parsons writes as follows:

“Our acquaintance commenced in 1836, at the Hunterian School of Medicine in Windmill-street, where we were both dissecting at that time. It happened that we usually overstayed our fellows, and often worked far on into the evening. The acquaintance thus grew into intimacy, which ended by our lodging and reading together. We were constant companions from that time till I left town, in October 1837. During that period Dr. Snow was, as a student, characterized by the same mental qualities which have marked him ever since. Not particularly quick of apprehension, or ready in invention, he yet always kept in the foreground by his indomitable perseverance and determination in following up whatever line of investigation was open to him. The object of this steady pursuit with him was always truth: the naked truth, for its own sake, was what he sought and loved. No consideration of honour or profit seemed to have power to bias his opinions on any subject. At the period of our co-residence he was a strict vegetarian, and many and great were the controversies held between us on the subject. These led to trials of our comparative strength and endurance, in one of which, on Easter Monday 1837, we walked to St. Alban’s, and back to town through Harrow,—a distance, I believe, of rather more than fifty miles. On reaching the Edgeware Road, my companion was fairly beaten, and obliged to reach home in an omnibus. But though this, you will say, shows a fair amount of strength, yet it was my impression that my friend’s constitutional powers were impaired by his mode of living, for I observed that he suffered from an amount of physical excitability not to be looked for in a man of his bodily powers and placid mental organization. I remember, on two or three occasions, so slight an injury as a cut of the finger with a dinner knife, or a graze of the skin, producing such an amount of fever, attended by so rapid a pulse, and so intense a flush upon the cheeks, that I once asked the opinion of an experienced medical friend about him, and was by that opinion alone restrained from summoning his uncle to his bedside. He also was subject to great drowsiness, so that he was obliged often to close his books, and retire to bed long before his inclination would have led him to do so.”

In October 1837, Mr. Snow took out his hospital practice at the Westminster Hospital. On May 2nd, 1838, he passed his examination, and was entered duly as a member of the Royal College of Surgeons of England. He lived at this time at 11, Bateman’s Buildings, Soho-square.

In July 1838, Mr. Thurnham having resigned his post of apothecary to the Westminster Hospital, Mr. Snow, with much promise of support from the medical staff, competed for the vacant post. He presented excellent testimonials from Mr. Hardcastle, Mr. James Allen of York, Dr. Conquest, Mr. W. B. Lynn, Surgeon to the Westminster Hospital, Mr. Anthony White, Sir Anthony Carlisle, Mr. Warburton, and Dr. Hunter Lane. His canvass was very satisfactory; but he was compelled to resign his claims from a cause which he did not expect. By the laws of the hospital, the office of apothecary could only be held by a member of the Apothecaries’ Company. In those days the worshipful Company were sometimes lenient in admitting students to examination. The leniency, however, clearly extended to those only who had friends at court. To render himself eligible, Mr. Snow addressed a very simple, earnest, and gentlemanly request to the Court of Examiners of the Apothecaries’ Company, begging to be allowed to go up to his examination at the second court in July instead of the first in October, at which he was legally admissible. The request, under the circumstances, was not very great; but for some reason it met with refusal. After the refusal he addressed a second note to the Court, equal in tone with the first. In this note he urged the simple character of the request; he reminded the sapient body that they had allowed a similar extension of privilege to that asked by himself to others, and even for less important reasons. He explained that he had attended the practice of the Newcastle Infirmary; and promised that if he could be admitted, he would fulfil the required term of hospital curriculum rigidly. Lastly, he stated the expenses into which the canvass had led him, and once more prayed for leniency of the examiners, from “confidence in their kindness”. The confidence was misplaced. The Blackfriars Shylocks demanded the pound of flesh; and our disappointed student, on the very eve of success, was compelled to relate his discomfiture in the following address:

“To the Governors of Westminster Hospital.

“My Lords, Ladies, and Gentlemen,

“I became a candidate for the vacant office of Apothecary to the Hospital a little before my term of study was completed, expecting that the Court of Examiners of the Apothecaries’ Company would admit me for examination in time for the election, knowing that they had granted a similar boon to my fellow-students on less important occasions. I have asked the favour of that Court with all due respect and ceremony, showing them that my course of study had already been twice as long as they require; and they have refused to examine me till my last item of study was completed according to their own peculiar curriculum, without stating any reason for their refusal. I must therefore necessarily resign, which I beg most respectfully to do, and to offer my sincere thanks to all those who have taken trouble in my behalf,”

On the first Court of October 1838, held on October 4th of that year, Mr. Snow met the Blackfriars Shylocks by legal right. They had not forgotten him, and gave him good proof of their remembrances. He passed, however, safe and sound; and, having the double qualification, laid himself out for the duties of a general practitioner in medicine in the great city.

At this time there existed in London a society (now sunken into the “Medical Society of London”) called the “Westminster Medical Society.” It was a society which had long given encouragement to those junior members of the medical profession who might wish for a hearing at its meetings and debates. Mr. Snow was not the man to lose an opportunity such as this. I have often heard him say, both privately and publicly, that, upon this early connexion with the “Westminster Medical,” his continuance in London depended, and all his succeeding scientific success. When he first attended the meetings of the “Westminster Medical,” he was very timid; and although he always spoke to the point, found it difficult to obtain a favourable notice. At first, as he told me, nobody ever replied to what he said. After a long time some grave counsellor condescended to refer to him as the “last speaker”. “In reference to an observation made by the last speaker, Mr. President, I could bring forward many practical objections; but I prefer to observe on the admirable, and, I have no hesitation in saying profound, remarks which Dr. Goldstick” (a very great gun, of course) “has done us the favour to lay before the society.” A little later and somebody ventured to name the “last speaker” even by his name. Then some one, bolder still, concurred with Mr. Snow; and ultimately Mr. Snow became recognized more and more, until, as we shall see in the sequel, the presidential honours were his own.

Frith-street, Soho-square, No. 54, was the house at which Mr. Snow, to use his own words, first “nailed up his colours”. He removed from Bateman’s Buildings in the beginning of September 1838, and became, in Frith-street, the tenant of Mrs. Williamson, widow of Captain Williamson, known as the author of several works on India. He bought no practice, nor exhibited any pretence. Like mighty Columbus, his caravel was very insignificant when compared with the voyage on which he embarked, and through which he sailed so successfully. He did not find the voyage very smooth either at first. How could he? A man cast at large in the modern Babylon, with few introductions, no plethora of purse, and great purposes in hand, need never ignore the necessities from the idea of rising to the crest of the wave by three cheers and a long pull. Snow was too foreseeing to be ignorant of this, and he prepared accordingly. A more thoroughly girded man for the world’s encounter could hardly be conceived than he at this time. He took no wine nor strong drink; he lived simply of the simple, on anchorite’s fare, with more than anchorite resolution, with the temptations of the world always before him; he clothed plainly, and made the best of everything; he kept no company, and found every amusement in his science books, his experiments, in his business, and in simple exercise.

To fill up time till the money patients should come, he became one of the visitors of the out-patients of Charing Cross Hospital; and to many a poor representative of the great half-starved, extended a skill which would have been a blessing to a duke. The Librarian of the College of Surgeons’ Library knew him as a quiet man, who read closely, and was not too proud to ask for a translation when an original bothered him. All who knew him said he was a quiet man, very reserved and peculiar—a clever man at bottom perchance, but not easy to be understood and very peculiar.

The connection with the “Westminster Medical” led to Mr. Snow’s first attempts at authorship. On October the 16th, 1841, he read at the Society a paper on “Asphyxia and on the Resuscitation of new-born Children.” The paper in full will be found in the London Medical Gazette for November the 5th of the same year. The paper is remarkable for the soundness of its reasonings, and the advanced knowledge which it displays. The object of the paper was to introduce to the Society a double air-pump, for supporting artificial respiration, invented by a Mr. Read, of Regent Circus. The instrument was so devised that by one action of the piston, the air in the lungs could be drawn into one of the cylinders, and by the reverse action, the said air could be driven away, and the lungs supplied with a stream of pure air from the second cylinder. There was also advanced, in the concluding part of the communication, a sentence or two on the cause of the first inspiration, which is well worthy of note. The cause of the first inspiration, he explained, is probably the same as the second or the last, viz., a sensation or impression arising from a want of oxygen in the system. So long as the placenta performs its functions, the fœtus is perfectly at ease, and feels no need of respiration; but whenever this communication between the child and its mother is interrupted, at least in the later months of pregnancy, the child makes convulsive efforts at respiration similar to those made by a drowning animal.

On December the 18th, 1841, Mr. Snow was again before the “Westminster Medical” with a very ingenious instrument which he had invented for performing the operation of paracentesis of the thorax. The description of the instrument will be found in the Medical Gazette of January 28th, 1842.

In the Medical Gazette for November 11th, 1842, Mr. Snow published a note on a new mode for securing the removal of the placenta in cases of retention with hæmorrhage; and in the same journal for March 3rd, 1843, he communicated an essay on the circulation in the capillary vessels. The essay was selected and rearranged from papers read before the “Westminster Medical” on January 21 and February the 4th. We have in this essay an admirable sketch of the capillary circulation. He advanced, on this occasion, the idea that the force of the heart is not alone sufficient to carry on the circulation, but that there is a force generated in the capillary system which assists the motion. He explained also the great importance of the cutaneous exhalation, and reasoned that in febrile states, accompanied with hot skin, the transpiration from the skin is in reality greater than is normal, and that the good effect of poultices and similar applications to inflamed skin is due to their influence in checking the transpiration from the affected part.

But what of practice during all this work at the purer science of medicine? The story to be told is an old one. Practice did not come, at least not from the wealthy. He had plenty of practice in so far as seeing patients was concerned certainly, for he was encumbered with four sick clubs; and his club practice, together with the out-patient work at the Charing Cross Hospital, kept the bell ringing all day, and not unfrequently enlivened the night with the clamorous music. But the patients with the fees in their hands kept at a respectful distance. Why? The answer gives another old story—because the practitioner at 54, Frith Street, Soho, was an earnest man, with not the least element of quackery in all his composition, with a retiring manner and a solid scepticism in relation to that routine malpractice which the people love. I have heard many reasons alleged for the want of success which attended Mr. Snow’s first labours as a claimant on the public confidence. These reasons have all had one reading, in that they refer to every cause but the true one. The true cause was, that a young man having no personal introduction to the bedsides of dowagers of the pillmania dynasty, sought to establish his fame on the basis of a sound and rational medicine—because impressed with the knowledge of the external origin of disease, he went in for the removal of external causes, and studied nature in preference to the Pharmacopœia.

Pushing on in the higher branches of his profession, and aiming always at the best, the degree of the University of London became a temptation, and Mr. became Dr. Snow on the 23rd of November, 1843, by passing the M.B. examination. He was enrolled in the second division on this occasion. On the 20th of December in the following year, he passed the M.D. examination, and came out in the first division of candidates.

The harass of London life by this time commenced to tell on Dr. Snow. He had suffered a few years previously from threatened symptoms of phthisis pulmonalis, but took plenty of fresh air, and recovered. He again became slowly unhinged for work, and in the summer of 1845, was attacked with acute and alarming symptoms of renal disorder. His friend and neighbour, Mr. Peter Marshall, then of Greek Street, now of Bedford Square, gave him his able assistance, and the advice of Dr. Prout, and, I believe, of Dr. Bright, was obtained. He was induced by their general opinion to change his mode of living, and even to take wine in small quantities. In the autumn of 1845, he paid a visit to his friend and old colleague, Mr. Joshua Parsons, at Beckington, with whom he stayed a fortnight, enjoying himself very much. The friends resumed their old controversies, and the Doctor admitted that he had been obliged to relinquish his vegetable diet in favour of a mixed regimen. He improved greatly, says Mr. Parsons, during his stay; but it was obvious that London life and hard study had hold of him. From Beckington he went to the Isle of Wight, but soon returned to London and to his work. A little after this, he was elected Lecturer on Forensic Medicine at the Aldersgate School of Medicine, and held the appointment till the establishment dissolved in 1849. I have often heard from him, in his quiet droll way, many laughable stories in relation to his duties in the forensic chair. When he left off teaching, he found that, in addition to the labour implied and the cost of experiments, he had to pay, with the rest of his colleagues, a ransom for his release.

There is no night without its morning. The eventful medical year of 1846 proved the turn of tide season with our struggling Esculapian. In this year, the news came over from America that operations could be performed without pain under the influence of sulphuric ether.

The fact was just such an one as would at once attract the earnest attention of Dr. Snow. It was a physiological, as well as a practical fact. It was rational in its meaning, and marvellously humane in its application. The question once before him, was in a scientific sense his own. His previous experimental studies on respiration and asphyxia had prepared him for this new inquiry. He lost no time, therefore, in investigating the new fact; he took it up for its own sake, however, not from any thought, at the time, of a harvest of gold.

The first inhalations of ether in this country were not so successful as to astonish all the surgeons, or to recommend etherization as a common practice. The distrust arose from the manner in which the agent was administered. Dr. Snow at once detected this circumstance; and, as he explains in the pages of the work now in the hands of the reader, remedied the mistake by making an improved inhaler. He next carried out many experiments on animals and on himself, and brought the administration to great perfection. One day, on coming out of one of the hospitals (I am giving the narrative as he gave it to me), he met Mr. —— (a druggist whom he knew) bustling along with a large ether apparatus under his arm. “Good morning!” said Dr. Snow. “Good morning to you, doctor!” said the friend; “but, don’t detain me, I am giving ether here and there and everywhere, and am getting quite into an ether practice. Good morning, doctor!” “Good morning to you!” Rather peculiar! said the doctor to himself; rather peculiar, certainly! for the man has not the remotest chemical or physiological idea on the subject. An “ether practice! If he can get an ether practice, perchance some scraps of the same thing might fall to a scientific unfortunate.” Consequently, with his improved inhaler, Dr. Snow lost no time in asking to be allowed to give ether at St. George’s Hospital. He got permission to give it there to the out-patients, in cases of tooth-drawing. Dr. Fuller, of Manchester-square, standing by, was surprised to see with what happy effects ether was administered when administered properly. A day or two afterwards, an operation having to be performed, and the surgeon (I believe, Mr. Cutler) not approving of the ether in the way in which it had previously acted, Dr. Fuller remarked on the superiority of Dr. Snow’s mode of administering it; and the result was, that he was asked to give it on operating days. He did so with great success. He administered it at University College with the same success. Liston, then the leading operator, struck with the new man who came before him in such an able and unaffected way, took him by the hand; and from that time the ether practice in London came almost exclusively to him. Science for once put assumption in its right place.

The new field once open, it were impossible but that he should cultivate it diligently. The Westminster Medical Society was often favoured with his communications and experiments on etherization; and in the September of 1847, he embodied, in his first work, the whole of his experience up to that time. The work was remarkable for the care with which it was written, the science which it displayed, and the complete mastery of the subject which it everywhere conveyed.

What had been a mere accidental discovery, I had almost said a lucky adventure, was turned by the touch of the master into a veritable science. The book was readily appreciated by the profession, and was just beginning to sell, when the discovery of the application of chloroform threw ether into the shade and the book with it.

Dr. Snow, though a man of great firmness when once his mind was made up, was always ready for new inquiry. Chloroform, therefore, was no sooner brought before the profession by Dr. Simpson, than he began to institute a series of independent researches, and having satisfied himself personally as to the effects and greater practicability of chloroform, he at once commenced its use, and forgot sooner almost than others all predilections for ether. In 1848, he commenced a series of experimental papers on narcotic vapours in the Medical Gazette, and continued them until 1851, when the Medical Gazette virtually ceased to exist. The papers on narcotics, in accordance with his other and earlier productions, were stamped with the evidences of profound and careful research, and still more careful deduction. I infer that they have been more talked about than read, for few people seem to be aware of the enlarged and positive physiological arguments which they contain. Chloroform and ether are not alone discussed, but all narcotics. Narcotics are not alone considered, but various of the great functions of life. The records of a vast number and variety of experiments are here related, and an amount of information, original in kind, collected, which will always remain as a memorable record in the history of medical literature. But the great points in these papers are those in which the author enters on the physiological action of narcotics. Here appear the generalizations and insights into the relations of allied phenomena which mark the man of true power. His greatest deduction on these matters, and the proofs on which it is based, are to be found in his observations, where he explains that the action of the volatile narcotics is that of arresting or limiting those combinations between the oxygen of the arterial blood and the tissues of the body, which are essential to sensation, volition, and all the animal functions. He demonstrated that these substances modify and, in large quantities, arrest the animal functions in the same way, and by the same power as that by which they modify and arrest combustion, the slow oxidation of phosphorus and other kinds of oxidation unconnected with the living body when they (the narcotics) are mixed with the atmospheric air.

In his modest way, he often spoke to me, with honest pride, on this observation. He himself thought it the best observation he had ever made, and believed that it would not be lost as an historical truth. Placing a taper, during one of our experiments, in a bottle through which chloroform vapour was diffused, and watching the declining flame, he once said, “There, now, is all that occurs in narcotism; but to submit the candle to the action of the narcotic without extinguishing it altogether, you must neither expose it to much vapour at once, nor subject it to the vapour too long; and this is all you can provide against in subjecting a man to the same influence. I could illustrate all the meaning of this great practical discovery of narcotism on a farthing candle, but I fear the experiment would be thought rather too commonplace.”

The year of the world’s fair in London, 1851, may be considered a fortunate one for Dr. Snow. His affairs had taken a new turn, and the tide was fairly in his favour. He had a positive holiday, physical and mental. The harass of the professional struggle was over, the world was opening its eyes to his intrinsic merits; old friends flocked around him, brought to the grand show in town, and all was well. He did but little this year, except to write a characteristic letter to Lord Campbell, who was pushing on a bill in the House of Lords, called the “Prevention of Offences Bill,” in which a clause was introduced to prevent, by severe punishment, any attempt that might be made by any person to administer chloroform or other stupifying drug for unlawful purposes. Dr. Snow, believing that Lord Campbell was actuated in introducing this clause by the fact of certain trials having recently occurred for the offence of using chloroform unlawfully, and being himself convinced that, in two of the cases (the one the case of a robbery in Thrale-street; the other, of a robbery attempted on London Bridge), the evidence against the prisoners, of attempting to produce insensibility by chloroform, was without any reason or possibility, he opposed the afore named clause in the bill on the ground that if it became law numerous frivolous and false charges would be constantly brought up against innocent people, or against guilty persons, but persons not guilty of the special charge laid against them, that, namely, of administering a volatile narcotic by inhalation. Knowing that weakness of human nature which leads a man, in the presence of all evidence, never to admit intoxication as possible in his own proper person, Dr. Snow felt that, in any case where an intoxicated person had been robbed, such person might allege that he had been made insensible by narcotic vapour. The two cases specially noticed in his letter admitted readily of such interpretation, and were clearly not cases in which chloroform had been administered. Lord Campbell, on the receipt of Dr. Snow’s letter, referred to it in very complimentary terms in the Lords’, but intimated that the reasoning of the letter did not alter his determination. The editor of the Medical Gazette, Dr. Alfred Taylor, opened fire on Dr. Snow; and for two or three weeks a sharp contest occurred between the two doctors; but the matter soon rested, each author retaining his own opinions, and both agreeing to differ.

Dr. Snow’s amiable but firm nature led him often to this ultimatum. Freedom of expression was a right he always claimed; but for this reason he extended the same privilege to others. He was never stirred into provocation by any difference of opinion. It was enough for him to form carefully his own opinions, and then to hold to what he had said, so long as he felt, from his internal convictions, that he was right.

In the year 1848, Dr. Snow, in the midst of his other occupations, turned his thoughts to the questions of the cause and propagation of cholera. He argued in his own mind that the poison of cholera must be a poison acting on the alimentary canal by being brought into direct contact with the alimentary mucous surface, and not by the inhalation of any effluvium. In all known diseases, so he reasoned, in which the blood is poisoned in the first instance, there are developed certain general symptoms, such as rigors, headache, and quickened pulse; and these symptoms all precede any local demonstration of disease. But in cholera this rule is broken; the symptoms are primarily seated in the alimentary canal, and all the after symptoms of a general kind are the results of the flux from the canal. His inference from this was, that the poison of cholera is taken direct into the canal by the mouth. This view led him to consider the mediums through which the poison is conveyed, and the nature of the poison itself. Several circumstances lent their aid in referring him to water as the chief, though not the only, medium, and to the excreted matters from the patient already stricken with cholera, as the poison. He first broached these ideas to Drs. Garrod and Parkes, early in 1848; but feeling that his data were not sufficiently clear, he waited for several months, and having in 1849 obtained more reliable data, he published his views in extenso in a pamphlet entitled “The Mode of Communication of Cholera”. During subsequent years, but specially during the great epidemic outbreak of the disease in London in 1854, intent to follow out his grand idea, he went systematically to his work. He laboured personally with untiring zeal. No one but those who knew him intimately can conceive how he laboured, at what cost, and at what risk. Wherever cholera was visitant, there was he in the midst. For the time, he laid aside as much as possible the emoluments of practice; and when even, by early rising and late taking rest, he found that all that might be learned was not, from the physical labour implied, within the grasp of one man, he paid for qualified labour. The result of his endeavours, in so far as scientific satisfaction is a realization, was truly realized, in the discovery of the statistical fact, that of 286 fatal attacks of cholera, in 1854, occurring in the south districts of the metropolis, where one water company, the Southwark and Vauxhall, supplied water charged with the London fæcal impurities, and another company, the Lambeth, supplied a pure water, the proportion of fatal cases to each 10,000 houses supplied by these waters, was to the Southwark and Vauxhall Company’s water 71, to the Lambeth 5.

There was, however, another fact during this epidemic, which more than the rest drew attention to Dr. Snow’s labours and deductions. In the latter part of August 1854, a terrific outbreak of cholera commenced in and about the neighbourhood of Broad-street, Golden-square. Within two hundred and fifty yards of the spot where Cambridge-street joins Broad-street, there were upwards of five hundred fatal attacks of cholera in ten days. To investigate this fearful epidemic was at once the selfimposed task of Dr. Snow. On the evening of Thursday, the 7th of September, the vestrymen of St. James’s were sitting in solemn consultation on the causes of the visitation. They might well be solemn, for such a panic possibly never existed in London since the days of the great plague. People fled from their homes as from instant death, leaving behind them, in their haste, all the mere matter which before they valued most. While, then, the vestrymen were in solemn deliberation, they were called to consider a new suggestion. A stranger had asked, in modest speech, for a brief hearing. Dr. Snow, the stranger in question, was admitted, and in few words explained his view of the “head and front of the offending”. He had fixed his attention on the Broad-street pump as the source and centre of the calamity. He advised the removal of the pump-handle as the grand prescription. The vestry was incredulous, but had the good sense to carry out the advice. The pump-handle was removed, and the plague was stayed. There arose hereupon much discussion amongst the learned, much sneering and jeering even; for the pump-handle removal was a fact too great for the abstruse science men who wanted to discover the cause of a great natural phenomenon in some overwhelming scientific problem. But it matters little. Men with great thoughts in their heads, think of little things which little men cover with their wide-spread feet. It matters little, for the plague was stayed; and whoever will now read dispassionately the report of a committee, afterwards published by the vestry, and the demonstrative evidence of the Rev. Mr. Whitehead, will find that the labours and suggestion of Dr. Snow, in reference to the Broad-street epidemic of cholera, must become each day better and better appreciated, as time, which never yet told a lie, tells the tale and points the moral of the event which is here so imperfectly described. Some who, at first, were amongst those who held up the labours of our friend to ridicule, or passed them over in contemptuous silence, have, indeed, since modified their opinions, and have either tacitly accepted his facts, or have done far worse by attempting to put them forward as though they were the work of no single man, or of some one unknown, or as though their connection with a theory destroyed the originality of the facts themselves. It was my privilege, during the life of Dr. Snow, to stand on his side. It is now my duty, in his death, as a biographer who feels that his work will not be lost, to claim for him not only the entire originality of the theory of the communication of cholera by the direct introduction of the excreted cholera poison into the alimentary system; but, independently of that theory, the entire originality of the discovery of a connection between impure water supply and choleraic disease. The whole of his inquiries in regard to cholera were published in 1855, in the second edition of his work on the “Mode of Communication of Cholera”—a work in the preparation and publication of which he spent more than £200 in hard cash, and realized in return scarcely so many shillings.

In 1856, he made a visit to Paris in company with his uncle, Mr. Empson, who having personally known the present Emperor many years, had on this occasion special imperial favours shown to him, in which the nephew participated. During the visit, Dr. Snow lodged a copy of his work on Cholera at the “Institute”, in competition for the prize of £1,200 offered for the discovery of a means for preventing or curing the disease. The decision of the judges has since been published, but no note seems to have been made of Dr. Snow’s researches.

The Medical Society of London, reformed under that name in 1849–50, by amalgamation with the Westminster Medical, was at this time the principal scene of Dr. Snow’s scientific exertions. In 1852, the Society elected him as Orator for the ensuing year; and at the eightieth anniversary of the Society, held on March the 8th, at the Thatched House Tavern, he delivered an admirable oration on “Continuous Molecular Changes, more particularly in their Relation to Epidemic Diseases.” He made no claim to the orator’s gown; but the address was too forcible and first class not to call forth the enthusiasm of the audience. It was admirably received; and few of us who were present on that interesting occasion will forget the simple and genuine earnestness of our beloved associate, as in the twinkling twilight he carried us along with the smooth current of his thoughts. He spent nearly twelve months in the preparation of this oration. It was intended to convey, in the most pleasing manner at his command, a broad view of his observations on the communication of certain spreading diseases. He advanced, on this occasion, the idea that intermittent fever, and perhaps yellow fever, are, like cholera, carried by their poisons direct into the alimentary system.

Two years after this event, having, meantime, passed the office of vice-president, the Society elected him to the highest honour it can confer,—to the presidential chair. He took his place as President, in his unassuming manner, on March 10th, 1855, delivering a short but pleasing address. Throughout the year he carried out the duties of his office with great success. One of his presidential acts was peculiarly graceful. One evening, while presiding, Dr. Clutterbuck (then the father, or oldest member of the Society) came into the meeting. The venerable and distinguished old man, then long past his eightieth year, had lately been a stranger to the assembly, and was known but to few of the members. The President, as Dr. Clutterbuck entered the room, himself rose, and in a way that was irresistible in its simple courtesy resigned his chair to the veteran Esculapian. “It is near fifty years,” said Dr. Clutterbuck with emotion, as he took the proffered seat, “since I last occupied this honourable position.” At the next anniversary meeting, held on March the 8th, 1856, Dr. Clutterbuck came to his last meeting, and to see (so the fates willed it) his friend the President play also his last part in presidential duties. At the anniversary dinner on that same day, the President reviewed, in feeling terms, his own career in the professional strife, and expressed that his success in life had originated in his acquaintance with the Society over which he then governed by the general will.

In addition to the fellowship of the Medical Society, Dr. Snow belonged to the Royal Medical and Chirurgical, Pathological, and Epidemiological societies. He was also a member of the British Medical Association. The Medical Society, from its old associations, was, however, that in which he took the most active part. Next to this, the Epidemiological Society claimed his regard. When Mr. Tucker first contemplated the formation of the Epidemiological Society, Dr. Snow was one of the first with whom he held consultation, and from whom he received that able support which enabled him to found that excellent institution. From the first of the Society, Dr. Snow was an active member. He was on many of its committees; he was a member of council, and a frequent contributor to its Transactions. He used often to meet with opponents to his peculiar opinions at the meetings of this Society, but he always retained friendships.

The position which he took as an epidemiologist was original, and in opposition to the views of many eminent men who had in the matters relating to public health considerable influence, scientific and political. He could not consequently, and did not, expect to go on his way unopposed. But he did sometimes expect a more deliberate and considerate attention to his hard wrought labours than he received or deserved. He used constantly, though no great professor of Shakespearian lore, to deplore the long admitted fact, that nothing so inevitably tends to transform an earnest inquiring and enthusiastic man, into a supercilious, superficial, and cold-hearted egotist, as translation from the stool of self-reliance and independence, into the gilded chair of office and brief authority.

It must be admitted that Dr. Snow’s views on the spread of epidemics were extreme in character; but from the slight which they too hastily received, they were not, I believe, properly understood. It has often been said that he encouraged by his arguments the perpetuation of certain offensive arts and occupations which are injurious to the public health; and in 1855, several journalists commented on him severely for this supposed error. But the fact is, he never presumed that any man could breathe with impunity other gaseous mixture than oxygen and nitrogen in atmospheric proportion. He knew too well the effect of inhaling chemical substances to allow of such supposition to enter his mind. But he contended, in regard to pure epidemic disorders, distinguished by specific symptoms, that these have a specific poison, which is propagated by certain fixed laws, which attains its progression and increase in and through animal bodies; which is communicated from one animal body to another, and which is the same in its essence from first to last. This was his position, and he adhered to it. No mere emanation arising from evolution of foul smelling gas can, per se, according to his views, originate a specific disease, such as small-pox or scarlet-fever; as well expect that the evolution of such gas should plant a plain with oaks or a garden with crocuses. True, small-pox may occur over a cesspool as an oak may spring up from a manure heap; but the small-pox would never appear over the cesspool in the absence of its specific poison; nor the oak rise from the manure heap in the absence of the acorn which seeded it.

In 1855, Dr. Snow gave evidence before the select committee on the “Public Health and Nuisances Removal Bill,” in which evidence he strove to convey the impressions which are condensed above. Feeling that he had not been correctly understood, he afterwards wrote a letter to Sir Benjamin Hall, in which he set forth the whole of his argument very distinctly and sensibly. He indicated in this letter that he was no defender of nuisances, but that whereas a bad smell cannot simply because it is a bad smell give rise to specific disease, so an offensive business conducted in a place where it ought not be should be proceeded against by ordinary law as a nuisance, without using in regard to it the word pestiferous, or otherwise dragging in and distorting the science of medicine. As time rolls on, it will probably be elicited that the groundwork of Dr. Snow’s theory is sound. That if he committed error, it was in adhering too closely to the abstract fact, and in not allowing sufficient importance to the favouring influence of impure conditions in the propagation and distribution of the specific poisons of the specific diseases.

At all events, the view he had maintained originally, he maintained to the end, and throughout conscientiously; and the aspersions that the object of his argument was to support his special theory regarding the communication of cholera, are utterly unfounded. In the present year, 1858, he read at the Epidemiological Society, and published in the Medical Times and Gazette, a repetition of his previous opinions, strengthening them by a statistical record, showing that the mortality of persons working at so-called offensive occupations is at certain ages lower, and at certain ages slightly higher, than in the general population. When the paper was read at the Epidemiological Society, Mr. Edwin Chadwick made a long series of objections to the paper, and complained that the argument was illogical. It was so, doubtless, on Mr. Chadwick’s premises; but on the premises advanced by Dr. Snow, as to the specific propagation of specific diseases by specific poisons, physiological problems on which, from his experimental researches and knowledge, he was far the best authority, his arguments were perfectly logical, and perfectly consistent.

In relation to public health, Dr. Snow contributed many other observations. In the first number of the Sanitary Review, he communicated a valuable paper, previously read at the Epidemiological Society, on the “Comparative Mortality of Town and Rural Districts”; and, previous to his decease, he was busily occupied in investigating the question of adulteration of bread with alum. He made several analyses of different specimens of bread, but his papers merely leave a brief record of the fact, without any comments or results.

We return for a few moments to some further points connected with his researches on inhalation. In addition to his experiments with volatile narcotics, he carried out for a long time a series of inquiries with other medicinal substances, and administered many remedies by inhalation at the Brompton Hospital, during a period of twenty months. In 1851, he recorded the result of this experience at the Medical Society of London, and explained the modes of administering various agents. Some, as morphia and stramonium, were inhaled with the aid of heat; others, as hydrocyanic acid and conia, were inhaled at the ordinary temperature. The particulars of these experiments will be found in a short paper in the London Journal of Medicine for January 1851.

He continued steadily to investigate the effects of various volatile agents for the production of insensibility, and arrived by frequent experiment to such a degree of positive knowledge regarding agents of this class, that the composition and boiling point of any new chemical body having been supplied, he could predict whether or not its vapour would produce narcotism by inhalation. Other than the volatile narcotics referred to in his present essay, he performed a variety of experiments with carbonic acid, carbonic oxide, cyanogen, hydrocyanic acid, Dutch liquid, ammonia, nitrogen, amylovinic ether, puff-ball smoke, allyle, cyanide of ethyle, chloride of amyle, a carbo-hydrogen from Rangoon tar, a carbo-hydrogen coming over with amylene, and various combinations of these. His grand search was for a narcotic vapour which, having the physical properties and practicability of chloroform, should, in its physiological effects, resemble ether in not producing, by any accident of administration, paralysis of the heart. The fact that in almost every fatal case from chloroform the result had occurred from the action of the narcotic on the central organ of the circulation, was never absent from his thoughts. An agent having this effect, however intrinsically valuable, was not to be put in the hands of every person for administration. “There would be a great uproar,” he remarked on one occasion, “if a student were to undertake on the operating table to tie the femoral artery, and were to open the femoral vein. Yet at some of our hospitals, the administration of chloroform has been entrusted to the porter, who would only grin in ignorance, if informed that each time his services were required, he performed the grand act of suspending for a time the oxidation of the whole body, and of inducing a temporary death; and who would tell you, if you asked him the composition of chloroform, that it was smelling stuff.” He spoke this from no selfish feeling, but with that kind of regret which an educated engineer would feel, on referring to the fact of a railway porter who, knowing nothing of steam, how to put it on, when to take it off, or why it propelled, had mounted an engine and driven a host of confiding passengers to their destruction. This is the way in which he expressed himself, and it would be difficult to show that he was not correct.

Intent on the discovery of some new anæsthetic, which might be more safely entrusted to general use, Dr. Snow began, in 1856, to experiment with amylene. As usual, he went to work cautiously and with precision. First he ascertained the boiling point of the specimen supplied to him; then the point of saturation of air with the vapour at different temperatures; then the effects of inhalation of the vapour by inferior animals, and the quantity required to be inspired, with the air breathed, to produce insensibility. These were the usual steps in all his inquiries of this kind. When he had obtained any substance which would produce insensibility favourably on animals, he pushed it, in one or two experiments, to its extreme in animals of different kinds; and having produced death by the inhalation, both by giving rapidly a large dose, and by giving a small dose for a long period, he observed the mode of death, whether it occurred by cessation of the heart, or by cessation of the respiration primarily. If the agent seemed to promise favourably from these inquiries, he commenced to try it on man; and the first man was invariably his own self. His friends, knowing his unflinching courage in the ardour of his inquiries, often expostulated with him in regard to the risks he ran. It was of no avail. He felt the personal trial a duty, and he did it. I do not believe, as some have supposed, that these personal experiments had any effect in producing his early death; but it is certain that he underwent many risks in the performance of his investigations, and that he held his own life of least consideration when the lives or well-being of others were under consideration.

There is yet another trait in his character which I cannot but notice, and which I would respectfully commend to all physiological inquirers. While he held it as a necessity to use inferior animals for the purpose of experiment, he never touched living thing with the physiologist’s finger without having before him some definite object; and never performed experiment on any animal without providing with scrupulous care against the infliction of all unnecessary suffering. The interests of humanity were, according to his rule, best advanced by the practice of a humanity that was universal.

He paid considerable attention to the subject of local anæsthesia, and tried numerous methods for attaining to a knowledge of a perfect local anæsthetic. He performed experiments with freezing mixtures, with chloroform; and for the production of rapid and efficient benumbing by cold, he tried, in 1854, the effects of applying solid carbonic acid to the skin. At one of the meetings of the Medical Society, he reported at length the results he had arrived at; but he was never satisfied with them, and soon relinquished the inquiry, in order to concentrate his energies on the discovery of what he felt sure must be discovered ultimately,—an anæsthetic which might be inhaled with absolute safety, and which would destroy common sensation without destroying consciousness.

To some extent he succeeded in this latter direction, in his discovery of the physiological effects of amylene; and for some time he was sanguine as to the great safety of the new agent. But the deaths which he has so faithfully recorded as occurring in his own hands from amylene, removed his expectations, and he discontinued its use as soon as he learned the risks which might follow its administration.

By his earnest labours Dr. Snow soon acquired a professional reputation, in relation to his knowledge of the action of anæsthetics, which spread far and wide; and the people, through the profession, looked up to him from all ranks, as the guide to whom to entrust themselves in “Lethe’s walk”. On April the 7th, 1853, he administered chloroform to Her Majesty at the birth of the Prince Leopold. A note in his diary records the event. The inhalation lasted fifty-three minutes. The chloroform was given on a handkerchief, in fifteen minim doses; and the Queen expressed herself as greatly relieved by the administration. He had previously been consulted on the occasion of the birth of Prince Arthur, in 1850, but had not been called in to render his services. Previous to the birth of Prince Leopold, he had been honoured with an interview with His Royal Highness the Prince Albert, and returned much overjoyed with the Prince’s kindness and great intelligence on the scientific points which had formed the subject of their conversation. On April 14th, 1857, another note in the diary records the fact of the second administration of chloroform to Her Majesty, at the birth of the Princess Beatrice. The chloroform again exerted its beneficent influence; and Her Majesty once more expressed herself as much satisfied with the result.

Inquisitive folk often overburthened Snow, after these events, with a multitude of questions of an unmeaning kind. He answered them all with goodnatured reserve. “Her Majesty is a model patient,” was his usual reply: a reply which, he once told me, seemed to answer every purpose, and was very true. One lady of an inquiring mind, to whom he was administering chloroform, got very loquacious during the period of excitement, and declared she would inhale no more of the vapour unless she were told what the Queen said, word for word, when she was taking it. Her Majesty, replied the dry doctor, asked no questions until she had breathed very much longer than you have; and if you will only go on in loyal imitation, I will tell you everything. The patient could not but follow the example held out to her. In a few seconds she forget all about Queen, Lords, and Commons; and when the time came for a renewal of hostilities, found that her clever witness had gone home to his dinner, leaving her with the thirst for knowledge still on her tongue.

From the literary and general history of Dr. Snow, let us turn for a few pages to his history personal. I will take the mean of the last eight years of his life,—the period in which I knew him,—as the period from which to draw particulars. He was of middle size, and, some years since, slender; but of late he had become of slightly fuller build. His long life in comparative student loneliness had made him reserved in manner to strangers; but with private friends he was always open, and of sweet companionship. With his increased popularity he became less reserved to strangers; and within the last few years he so far threw off restraint as to visit the opera occasionally. But he moderated every enjoyment, and let nothing personal stand in the way of his scientific pursuits. He was the impersonation of order. He had his time and place for everything; he kept a diary, in which he recorded the particulars of every case in which he administered chloroform or other anæsthetic, with comments on the results of the administration, and hints as to dangers avoided or chanced. He kept a record of all his experiments, and short notes of observations made by his friends. He rose early, and retired early to rest,—at eleven o’clock. He seemed, whenever he was waited on, as though he had nothing in hand, and were always open to an engagement.

Anything and everything of scientific interest arrested his attention, and his kindliness of heart was at all times in the foreground. When I was living at Mortlake, he would run down, on request, after his day’s duties were over, to a post-mortem, to see a poor patient, or to take part in an experiment, returning as cheerily as though he had been to receive the heaviest fee. I name this as but one example of his kindly nature; there are many who could corroborate the example in like personal manner.

He laid no claim to eloquence, nor had he that gift. A peculiar huskiness of voice, indeed, rendered first hearings from him painful; but this was soon felt less on acquaintance, and the ear once accustomed to the peculiarity, the mind was quickly interested in the matter of his discourse, for he always spoke earnestly, clearly, and to the point. In the societies he spoke very often, and gave expression to views, on which he had spent great thought, with a generous freedom which, in so far as the fame of his originality was concerned, had been better held in reserve. It had been better, that is to say, for him to have carefully elaborated some of his views in the closet, and published them fully, than to have sent them forth in the hurry of debate. Had he lived, he would possibly have collected many stray labours thus put forward, and have given to them the matured consideration which they deserved. One of his views, on which he would have bestowed great attention, refers to the origin of various morbid growths, as cancer. He believed that these morbid formations are all of local origin; that they arise in the parts of the body where they are found, from some perversion of nutrition; and that the constitutional effects are secondary to and dependent on the local disorder. He had made many observations on this important subject, notices of which are to be found scattered, here and there, in the proceedings of the Medical Society of London, but no connected record was ever completed.

His private conversation was both instructive and amusing; he was full of humorous anecdotes, which he told in a quiet, and irresistibly droll style; and when he laughed, his goodnatured face laughed in every feature.[^[1]] His anecdotes were never given in set form, but were elicited by some circumstance or other which might happen to suggest them. Once, when a friend of ours related at dinner some of the economical measures of an odd old doctor who was known to some of the company, he gave us an anecdote, showing how a man may work too hard for his money. “When I was a very young man,” he said, “I went for a brief period to assist a gentleman who had a large parochial practice. I found his surgery in a very disorderly state, and thinking on my first day with him that I would enhance myself in his opinion by my industry, I set to work, as soon as his back was turned, to cleanse the Augean stable. I took off my coat, cleared out every drawer, relieved the counter of its unnecessary covering, relabelled the bottles, and got everything as clean as a new pin. When the doctor returned, he was quite taken by storm with the change, and commenced to prescribe in his day book. There was a patient who required a blister, and the worthy doctor, to make dispensing short, put his hand into a drawer to produce one. To his horror, the drawer was cleansed. Goodness! cried he, why where are all the blisters? The blisters, I replied, the blisters in that drawer? I burnt them all; they were old ones. Nay, my good fellow, was the answer, that is, the most extravagant act I ever heard of; such proceedings would ruin a parish doctor. Why, I make all my parochial people return their blisters when they have done with them. One good blister is enough for at least half a dozen patients. You must never do such a thing again, indeed you must not. I did not, for he and I soon found a good many miles of ground between us, though we never had any more serious misunderstanding.”

His replies, when under the fire of cross-question, were ready and commonsense. Once, he observed that in his opinion sulphuric ether was a safer narcotic than chloroform. Why, then, said a listener, do you not use ether? I use chloroform, he resumed, for the same reason that you use phosphorus matches instead of the tinder box. An occasional risk never stands in the way of ready applicability. On another occasion, after one of the meetings of the “Medical Society,” when the subject of a specific cholera cell had been under debate, some one asked him, as a poser and rather ironically, where he thought the first cholera cell came from? “Exactly,” he replied, with a droll face. “But to begin, do you tell me where the first tiger or the first upas tree came from; nay, tell me where you came from yourself, and I will then tell you the origin of the first cholera cell, and give you the full history of the first case; but I want a model before I venture on the description of ultimate facts.”

As an author, his style was plain, clear, and smoothly elegant. His argument was always carefully studied and as carefully rendered. He sent manuscript to the printer which required scarcely a letter of correction. Both in writing and speaking, he made the expression of truth his first business. Neither provocation nor temptation could ever lead him aside from that principle. His readings were select. He chiefly read scientific works, old and new. He had great relish for some of the old medical writers—the masters in physic. He had read Bacon, but agreed with Harvey’s criticism that Bacon wrote science like a lord chancellor. He had a notion that there had been a history long previous to any we know of from existing records, in which the sciences generally had risen to a greater perfection than they are at this present. His conversance with Sprengel’s History of Medicine had possibly led him to this opinion. He was fond of general history also, but studied it little. He never read novels, because the hours devoted to them were, he felt, hours thrown away. At the same time, he enjoyed as much as any man ridiculous life-pictures naturally cast. When he came to see me, and leisure was with us, I used often to read to him some of the more amusing passages from Dickens and Thackeray, or from one of the older writers, as Swift. It was a new world to him, and provoked great fun. He would ask to have passages read over again, that he might better realize the conception. He enjoyed vastly any anecdotes about the old men in physic, the Cullens and Meads and Arbuthnotts and Harveys. Any such anecdotes he took into his memory and never forgot them.

On such occasions I would, in ridiculous mood, sing him absurd songs to any tune, two or three tunes, or to no tune at all, and without any pretence at voice. At first he would listen with his hands flat together and with a perfect melancholy on his face, as if he could hear it no longer. Bit by bit he would relax, and at last get into a continued laughter. Then I would stop, and he would begin to open out his list of anecdotes, professional and general, upon which the laughter came over to me with compound interest, for of men enriched with stores of droll stories, few could equal him. Nor was he inventive in these narrations; he had simply observed character shrewdly, and described it in its humorous phases. If he had written as he related, he would have ranked as one of the humorists of the age of no second order.

He thought severely of the reviewer’s art, and would never of late review any book critically. If a book were good, it carried the review of its own merits. If it were bad, it were better left untouched. He, at all events, with so much original work before him, could not stop to criticize his compeers or their transactions. Let the dead bury their dead; he must march with the living while life gave power.

Notwithstanding, he was fond of controversy and courted it. I expressed to him once some surprise that he with such an even temper should write so often in controversial style; and that surely it were better to follow Harvey’s and old Sam Johnson’s plan, to do the best oneself, and leave the controversy altogether to others less personally influenced. He agreed that this was by far the best system, but did not think it practicable generally, and feared that silence might often be misinterpreted.

Men who have something in them take different courses in the way of accepting the world’s recognition of their labours. The beginning, in most cases, is after a given pattern; the end is modified and turned about variously, according to the stamp of the man. All start with an exaggerated appreciation of their own doings, and with exaggerated feelings respecting the critics who first notice them. The critic is Jove the all wise, or Pluto the all black. There was never middleman critic yet. Some men stop at the first, either too elated with the pleasure of the first reception to venture more, or too cast down from the pain of a sharp reception to tempt fortune further. Cowards these both, in one word. Others enter into violent controversies; in the heat of the same, drop one or two contradictions, and, wishing every month that Cadmus had been still born, go on always at controversy, boring everybody, and especially those who would believe if not bored. Others, again, soon find their own level, and not only their own, but the level of their critics. Surfeited with commendation, or hardened by attacks, these care little for either, and make no retorts save such as are by ambuscade and go right home. A fourth class, of immovable temper and self-reliant, fall into what seems, superficially, indifference, but which means, deeply, the soul of earnestness. These do always the best thing at the time, and, when it is done to their own satisfaction, put it forward, with no anxiety whatever as to what may be said of it, with no intention of entering into any defence of it, and with no intention of doing anything less than themselves correct all such errors in it as after knowledge may indicate, or commit it to the flames, if destruction be its best fate. Fatalists in letters, men of this class, if it be pleasure to call them so; but great fatalists too—honest reviewers of their own works, who fear their own criticisms, and none other; who offer immense labours, and die to them as they offer. Dr. Snow, as we have seen, was the representative rather of the controversial class of workers. But he had his own way of doing the controversy business, which saved friendships, and exhibited a firm principle and an exact knowledge. It is not to be denied, however, that, had he put his labours before the world, and trusted in them and on the world’s justice, never replying a syllable, he would have avoided an extremity of argument which was often not merely unnecessary in relation to his propositions, but injurious to them, as reasonings overstrained.

He admired art, and felt real pleasure in advancing it. He enjoyed innocent recreations, and was ever at home in the family circle. He had his regrets that he had never married, the fates had been against him permanently on that score. He loved the prattle of children. When he went to court during last season, and had arrayed himself in his court suit, nothing connected with the event amused him so much as the saying of the child of a friend, who, on seeing him start, with his sword and flattened hat, held up her hands, and exclaimed: “Oh! isn’t Dr. Snow pretty, mamma.” The idea of being considered pretty roused in him quite a new and droll sensation, which he could not help telling about as a rare incident in a courtier’s career. The anecdote is simple, but it gives a good idea of the simple and genial nature of the man.

It has been shown that the tendency of Dr. Snow’s mind for philosophical pursuits led him away in some measure from the practical drudgery of professional life. From this fact, it has been too hastily inferred that he was therefore, in the common parlance, “not a practitioner.” Those who knew him as a practitioner, who had had the advantage of his assistance in cases of doubt or difficulty, have a very different opinion. These speak of him, with one accord, as having been, without any ostentation, one of the soundest and most acute of our modern physicians. He had great tact in diagnosis; an observant eye, a ready ear, a sound judgment, a memory admirably stored with the recollection of cases bearing on the one in point, and a faculty of grouping together symptoms and foreshadowing results, which very few men possess. Mr. Peter Marshall, of Bedford Square, who often called in Dr. Snow in consultation, has remarked to me in nearly the same terms as I have expressed, his independent appreciation of Dr. Snow’s practical knowledge. For my part, I never had the good fortune to put many fees into his pocket; but as I had often the pleasure of meeting him on pure scientific grounds in cases of interest, I can bear truthful testimony to his eminent qualities as a practitioner, and to the fact that his philosophical labours only served to render him more intelligent and profound in matters relating to diseases and their treatment. He did not become the idol of the people in common practice, far from it: but the failure arose not from deficiency of knowledge, but from a more perfect knowledge with assumption whipped out of it. It is no discredit to his memory that he was not the idol of the people in common practice, though it cost him much suffering to feel himself kept down, by that wisdom which is the oil to the water of popular ignorance concerning life and its laws. For, to be the idol of the people in physic, is too often to be the Juggernaut of physic,—an idol of wood or of stone in showy gold and tinsel. This idol has neither sense nor force; if it had, it were not an idol; it would walk off, or tell the worshippers no longer to shake hands constantly with themselves in its presence.

But, when the opportunity offered for obtaining remunerative practice by the exercise of his scientific skill, Snow showed himself, both in act and industry, competent for success. He soon overcame all difficulties, and managed by his frugality to lay in store for a rainy day for himself, and to help such friends as needed. Many rumours as to the extent of his gains abound which it is right to correct. His income of late years was near £1,000 a year, but it never exceeded that sum. For this, he exhibited chloroform or one or other anæsthetic about four hundred and fifty times annually, taking an average of the ten years preceding his death. In a large number of these cases, however, his services were gratuitously supplied.

In his private relations, Dr. Snow was a man of the strictest integrity and purest honour. The experiences of life, instead of entwining about him the vices of the world, had weaned him from the world. Without any pretence, maintaining no connection with sect or party, living by the rules of the eternal laws which, according to the best of his abilities, he could read from the universe, he carried out a practical religion, independently of any hypothesis or abstruse profession, which few professors could approach. A child of nature, he knew no way of recognizing the Divine influences so purely as in silent and inexpressible admiration of those grand external phenomena which pharisees see not, but which each moment convey to men of his character, the direct impression of a Power all present and revealing itself for ever.

We approach the end. In the midst of his success, when medicine most needed him and his hand was most powerful, he stood one day in his mental strength, and the next day fell. Death found him at his work, and the stern enemy came on him suddenly, though not without forewarnings.[^[2]]

His health had long been indifferent; he had suffered from hæmatemesis several times in the last few years, for which Dr. Budd had attended him, and he had his own forebodings that his life was not of the longest. In the month of December 1857 he was suddenly seized one evening with vertigo and sickness, which compelled him to keep the recumbent position for more than twenty-four hours. At the end of this time he felt better, and went about his usual avocations. He had no convulsions at this time, nor did he lose his consciousness. After this attack, he complained on many different occasions, both to his housekeeper and to several of his medical friends, of numbness in his extremities. Some of these to whom he mentioned this circumstance, do not recollect whether this symptom was greater on one side of the body than on the other; while others distinctly state that it was referred to the left side only. His housekeeper was certain that he never complained of this numbness before the attack in December; and even afterwards, it would appear to have been only an occasional symptom. For six weeks before his final seizure he had made no mention of it. About three weeks before his last attack, he had complained, for some days, of a severe pain in the back of his head, which he himself considered neuralgic, and for which he treated himself. This pain quite left him, and for about a fortnight he had been enjoying excellent health.

On the evening of Tuesday, June the 8th, 1858, he attended a meeting of the Royal Medical and Chirurgical Society. On the following evening there was a meeting of a private society for the study of chest diseases, held at Dr. Quain’s. The subject discussed was the cause of the first sound of the heart. On this, the last occasion of the kind at which he was present, he was in unusual spirits, and looked exceedingly well. He entered into the debate with great earnestness, agreed to form one of a committee to inquire into the cause of the first sound by experiment, and left his friends with enthusiastic expression as to the success of the proposed undertaking. We exchanged our last farewells that night.

He went to bed at half-past eleven o’clock on June 9th, and on the following morning he came down stairs at 8 A.M. When he came down, he complained to his housekeeper of slight giddiness, and she thought he did not walk very steadily. He reclined on the sofa, and said that he should be well again in a few minutes, but that he did not think he could eat any breakfast. Soon after, however, he got up, said he felt very hungry, and ate a very hearty breakfast. When this was done, he proceeded to write a portion of the manuscript of the work on anæsthetics now published. He had written to the last printed sentence, when his housekeeper, who had scarcely left him, heard a great noise, as if some one had fallen. She ran up again and found her master on the floor, making vain endeavours to regain his chair. He does not appear to have had any convulsions, and his consciousness was unimpaired, for he remarked when his housekeeper came into the room, that though he did not quite understand the nature of his complaint, he was very sure he never had had any such symptoms before. His housekeeper observed that he had quite lost all power over his left arm and leg, and that his mouth appeared drawn to the right side. She had him lifted on the sofa; and here he remained for twenty-four hours before any medical assistance was sent for. This was his own wish, as he said he should soon be better, and that he did not wish to trouble any one. During this period he complained much of pain over the lower end of the sternum, which he endeavoured to relieve by frequent inhalations of sulphuric ether, but he neither ate nor slept the whole time. At 6 A.M. on the morning of Friday, June 11th, retching came on, and he vomited a considerable quantity of blood. Upon this his housekeeper sent for Dr. Budd, who, along with Dr. Murchison, continued to attend him to the last. His symptoms, when seen by these gentlemen, were briefly as follows:—Complete paralysis of motion over the whole of the left side of the body, but without loss of sensibility; the left angle of the mouth falling down, and the apex of the tongue deviating to the left; memory and consciousness were unimpaired; there was pain and great tenderness in the epigastrium, with urgent hiccup and hæmatemesis; there were slight indications of albuminuria, but there were no dropsical symptoms.

The hæmatemesis ceased after about twenty-four hours, but the vomiting and hiccup continued. By Monday, the 14th, these symptoms also had subsided, but others of a more alarming nature began to show themselves. The pulse and respiration became accelerated, the countenance and extremities became livid, and there was occasional wandering delirium. These symptoms gradually increased in severity; but he retained his consciousness until 11 A.M. of Wednesday, June 16th, when the breathing became stertorous, and deglutition impossible. Throughout his illness, he had been sanguine of recovery, and expressed his belief frequently that he should soon be at his professional work again. On this, the last morning of his life, the fact of the danger in which he was placed was explained. He met the intelligence with calmness, but felt a wish to see Dr. Todd. Soon he sank into a somnolent state approaching to dissolution, and at 3 P.M. death took him.[^[3]]

On the Monday following, Dr. Snow was buried at the Brompton Cemetery. It was the wish of many of his medical friends to follow him to his last home. But his relations, recalling his own unostentatious feelings, laid him in the grave in simple ceremony; and there, ingenuous friend, in the sleep that knows no waking, he sleeps on and takes his rest; the rest he has earned. The old changes of the world live after him, women mourning for their children; youths exulting on the marriage day; the inanimate returning to the elements; the animate returning to the infinite. But in the gaping time shall it chance rarely, for another science-man to come and go, who, taking him all in all, may call him “brother”!

HISTORICAL INTRODUCTION.

The most important discovery that has been made in the practice of medicine since the introduction of vaccination, is, undoubtedly, the power of making persons perfectly insensible to the most painful surgical operations, by the inhalation of the vapours of ether, chloroform, and other agents of the same kind.

In giving a brief outline of this discovery, it is necessary to inquire into the attempts of every kind which had previously been made to prevent severe pain; and also to notice the history of medicinal inhalations, whether undertaken with the view of preventing pain, or of relieving or curing disease.

The practice of taking opium and other vegetable narcotics, to relieve pain or procure sleep, was common in the most remote periods to which history extends; but the earliest notices which remain of any attempts to prevent the pain of surgical operations were written at the period of the Roman Empire. They were alluded to by Dr. Simpson at the Medico-Chirurgical Society of Edinburgh in November, 1847.[^[4]] Dioscorides,[^[5]] speaking of mandragora, says, “Some persons boil the root in wine down to a third part, and preserve the decoction, of which they administer a cyathus (rather more than an ounce and a half) in want of sleep and severe pains of any part, and also before operations with the knife or the actual cautery, that they may not be felt.” (Ante sectiones ustionesve, ut ne sentiantur.) Further on he says: “A wine is prepared from the bark of the root without boiling, and three pounds of it are put into a cadus (about eighteen gallons) of sweet wine, and three cyathi of this are given to those who require to be cut or cauterized: when being thrown into a deep sleep they do not feel any pain.”

The same author also adds,[^[6]] in speaking of a kind of mandragora called morion, “They relate that a drachm of it being taken as a draught, or eaten in a cake or other food, causes infatuation, and takes away the use of the reason. The person sleeps without sense, in the attitude in which he ate it, for three or four hours afterwards. Medical men also use it when they have to resort to cutting or burning.”

In treating of mandragora, Pliny[^[7]] remarks that the juice of the leaves is more powerful than the preparations made from the root. He says, “Some persons even die from a considerable draught. It has the power of causing sleep in those who take it. The dose is half a cyathus (six drachms). It is taken against serpents, and before cuttings and puncturings, lest they be felt. For these purposes it is sufficient for some persons to have sought sleep from the smell (of the medicine).”

Apuleius,[^[8]] under the head mandragora, says, “If any one eat it he will immediately die, unless he be treated with butter and honey, and vomit quickly. Further, if any one is to have a limb mutilated, burnt, or sawn, he may drink half an ounce with wine, and whilst he sleeps the member may be cut off without any pain or sense.”

After reading the above passages from such well-known authors, it may be asked how it was that the practice of preventing the pain of surgical operations was entirely unknown just prior to 1846.

The reason, no doubt, was that the statement these passages contain was looked upon as a vulgar error of the period, which had imposed on the credulity of the authors. Dr. Woodville,[^[9]] speaking of the use of mandragora by the ancients, says, “They employed it principally in continued watchings, and in those more painful and obstinate affections which were found to resist less powerful medicines.” He gives, in a foot note, a reference to the place in Dioscorides from which the passages above quoted are taken, and had he believed in the performance of operations without pain, we may conclude he would not have passed over so important a fact in silence.

With the knowledge we at present possess, however, a different view must be taken of the subject; and it must at least be allowed that the statements of the ancients had some foundation in truth. This is rendered more certain by the circumstance that atropa mandragora belongs to the same genus as belladonna, which has a greater power in annulling the common sensibility than any plant in present use, unless it be aconite. The loss of reason, described by Dioscorides as caused by mandragora, is a striking symptom of poisoning by the class of plants (the solanaceæ) to which it belongs. It appears from some remarks of Aretæus[^[10]] and Cælius Aurelianus[^[11]] that people were in the habit of taking mandragora as an inebriating agent in the time of the ancients, as an allied plant, the datura, is used at present by the natives of India. This practice would lead to a correct knowledge of the quantity which might be taken with impunity.

The mandrake is scarcely used in medicine at present, but its narcotic properties are well established. Hoffberg[^[12]] administered the root in doses of three grains in some cases of gout, with the effect of relieving the pain.

Cases of poisoning by belladonna end, with very few exceptions, in recovery, however large the dose, and however alarming the symptoms may be; and, taking all the above circumstances into account, it is probable, that after ascertaining the right quantity to be administered for the purpose, this medicine or mandragora might be used, with considerable success, and no great danger, to prevent the pain of operations, if chemistry had not supplied us with agents much more convenient.

Not many ages after the Greek and Roman authors above quoted were describing the effects of mandrake in preventing the pain of operations, another plant, the Indian hemp, was employed for the same purpose in a more remote part of the world. M. Stanislas Julien, in an article on Chinese Medicine,[^[13]] gives a notice of a work entitled “Koukin-i-tong, or a General Collection of Ancient and Modern Medicine,” in fifty volumes, 4to., and makes an extract from it respecting Hoa-tho, a practitioner, who flourished under the dynasty of Wei, between 220 and 230 of our era. Respecting Hoa-tho, it is stated that—“When he found that it was necessary to employ acupuncture, he applied it in two or three places; he did the same with the moxa, if it was indicated by the nature of the affection which he had to treat. But if the malady was situated in parts on which the needle, the moxa, or liquid medicines could not act—for example, in the bones, in the medulla of the bones, in the stomach, or the intestines, he gave to the patient a preparation of hemp (Ma-yo), and, at the end of some instants, he became as insensible as if he had been drunk, or deprived of life. Then, according to the case, he made openings and incisions, performed amputations, and removed the cause of mischief; he then brought together the tissues with points of suture, and applied liniments. After a certain number of days (at the end of a month, according to the annals of the later Hân) the patient found himself reestablished, without having experienced the slightest pain during the operation.”

We are not informed of the way in which the hemp was administered. If insensibility was caused so quickly, as is stated, it must have been by inhaling the fumes of the hemp when exposed to heat, and not by taking it into the stomach. This view of the matter is rendered more probable by the circumstance that the ancient Scythians were in the habit of inhaling the fumes of hemp,[^[14]] several centuries before the time of Hoa-tho, and also by the practice of the Hindoos at present, who inhale the fumes of hemp from a pipe. The remark that the patient became reestablished at the end of a certain number of days, must refer to his recovery from the wound caused by the operation, and we are not informed how long the state of insensibility continued.

The next notice of any attempt to prevent the pain of operations, that I am aware of, occurs in the work on Surgery of Theodoric, an author who lived in Italy in the latter half of the thirteenth century. He writes as follows:[^[15]] “The making of a flavour for performing surgical operations according to Dominus Hugo. It is thus made:—take of opium, of the juice of the unripe mulberry, of hyoscyamus, of the juice of hemlock, of the juice of the leaves of mandragora, of the juice of the woody ivy, of the juice of the forest mulberry, of the seeds of lettuce, of the seeds of the dock, which has large round apples, and of the water hemlock [cicuta]—each an ounce; mix all these in a brazen vessel, and then place in it a new sponge; let the whole boil, as long as the sun lasts on the dog days, until the sponge consumes it all, and it is boiled away in it (the sponge). As oft as there shall be need of it, place this sponge in hot water for an hour, and let it be applied to the nostrils of him who is to be operated on, until he has fallen asleep; and so let the surgery be performed. This being finished, in order to awaken him, apply another sponge, dipped in vinegar, frequently to the nose, or throw the juice of the root of fenugrek into the nostrils; shortly he awakes.”

I altogether disbelieve that a sponge, prepared as above, would, after being placed in hot water, give off any odour or vapour which would cause insensibility. The active ingredients, as they exist in the various plants, are not sufficiently volatile to be given off at a heat below that of boiling water. Hemlock, indeed, contains a volatile principle, which can be liberated by an alkali; but, even if it were set free by any chance during the preparation of the sponge, it would all be dissipated by the long boiling.

If sleep were really caused in this way, it must have been by some of the moisture from the sponge reaching the mouth or throat, and being swallowed; and it may be remarked that the author speaks of the preparation of a taste or flavour (confectio saporis), rather than an odour, although the sponge is certainly directed to be applied to the nostrils. It must be remarked, also, that if the patient were made so insensible, as not to feel the surgeon’s knife, he would be little affected by vinegar, or the juice of fenugrek, in his nostrils.

Immediately after the prescription quoted above, and in the same paragraph with it, Theodoric gives another recipe from Master Hugo, directing antimony, quicksilver, soap, quick lime, and a little arsenic, to be sublimed together. A portion of the resulting compound, the size of a nut, is directed to be placed over a hernia, or whatever else is to be operated on. Then follows a rather lengthy direction for subliming arsenic, also from Dominus Hugo. The arsenic so sublimed is described as rendering surgical operations extremely pleasant. The words are—“hæc acus fiat mitis et suavis: sicut sudor beatæ virginis quum peperit Christum.”

I have applied arsenic to the skin for twenty-four hours, with no other effect than irritation, and an eruption of pimples, the sensibility of the part being increased; and in my opinion, arsenic would not cause insensibility, unless it were applied so long that the inflammation caused by it should end in gangrene. I consider that the statement of Theodoric, respecting arsenic, strengthens the doubts I have expressed concerning his spongia somnifera. There is another reason for disputing the efficiency of the above mentioned recipes. Theodoric directs the patients about to undergo operations to be tied, or held by strong men. In the operation for hernia, for instance, he directs the patient to be tied to the bench, or table, with three bands, one round the ankles, another round the thighs, and a third across the chest, holding the arms and hands. This circumstance is the more significant, since Theodoric had lived some time with Hugo, and seen his practice, as he states in the dedication to his work.

It is reasonable also to conclude that if any successful plan of preventing the pain of surgical operations had been introduced after the revival of literature, it would not have fallen into disuse and been forgotten.

In an interesting paper by Dr. Silvester,[^[16]] an anecdote is quoted, with an intention to show that anæsthetics were commonly had recourse to in severe operations as late as the end of the seventeenth century. The quotation is from a German work by A. G. Meissner, called Skizzen, or Sketches, and published at Carlsruhe in 1782. It is as follows:—

“Augustus, King of Poland and Elector of Saxony, suffered from a wound in his foot, which threatened to mortify. The court medical men were opposed to the operation of amputation; but during sleep, induced by a certain potion surreptitiously administered, his favourite surgeon, Weiss, a pupil of Petit, of Paris, cut off the decaying parts. The royal patient was disturbed by the proceeding, and inquired what was being done, but on receiving a soothing answer he again fell asleep, and did not discover till the following morning, after his usual examination, that the operation of amputation had really been performed.”

It is most probable that the potion surreptitiously administered in this case, was an ordinary sleeping draught, and that only the “decaying parts” were cut off, as in fact is stated. The decaying parts of course would be without feeling.

The mind of surgeons seems now and then to have turned spontaneously towards preventing or alleviating the pain of operations, and certain attempts and suggestions were made with this object during the later part of the last century, in apparent ignorance of what had been done by the ancients in this direction.

Ambroise Tranquille Sassard, principal surgeon of the Hospital la Charité at Paris, recommended the employment of a narcotic previous to serious and painful operations, the dose to be proportioned to the age and strength of the patient.[^[17]] He does not state whether the plan was actually tried.

Mr. James Moore, surgeon,[^[18]] recommended compression of the large nerves, and tried it on a patient in St. George’s Hospital, whose leg Mr. John Hunter amputated below the knee. The crural and sciatic nerves were compressed for nearly an hour by an instrument contrived for the purpose, and Mr. Moore considered that the greater part of the pain was prevented. The patient complained more of the sawing of the bone than of the cutting part of the operation. I am not aware whether this plan was tried in other instances, but it is certain that it did not come into general use.

M. le docteur Liégard (de Caen) has stated,[^[19]] that the peasants in his part of France are in the habit of tying a band very tightly round the arm or leg before operations on the extremities. He had himself removed a toe-nail in two cases, without pain, after a handkerchief had been tied very tightly round the lower part of the leg. By this measure both the nerves and blood vessels are, of course, more or less compressed.

The persons who believe in the existence of a force or power, which they call Mesmerism, or animal magnetism, made many and persevering efforts in recent times to cause insensibility to the surgeon’s knife. In some cases they were imposed on by dishonest and designing patients, who afterwards confessed they had suffered the pain to which they had pretended to be insensible, but in other cases I have no doubt of the operations having really been performed without pain. Absence of consciousness and sensation is a common symptom in many cases of hysteria and catalepsy, and in certain susceptible persons, hysteria and catalepsy, or conditions nearly resembling them, can be induced by acting on the imagination, or by exhausting the attention by means of the fixed stare and monotonous “passes” of the so-called Mesmerisers.

Dr. Esdaile was more successful in putting Hindoos to sleep, and operating on them in the hypnotized[^[20]] state, than any one has been with Europeans: yet it was only in a portion of the cases in which it was tried that the alleged agent took effect. In many instances, efforts continued for two or three months had no effect on the patient; and in many of the operations, which were reported as successful, “there was much convulsive movement of the limbs, corrugation of the brows, and even loud cries and sobs,” although the patients afterwards denied all knowledge of what had passed.[^[21]]

The discovery of the means of preventing pain, which will occupy the greater number of the following pages, did not arise out of any of the attempts either in ancient or modern times above enumerated. It sprung directly from the practice of inhaling chemical and medicinal substances.

The custom of inhaling the fumes of narcotic plants existed at the very commencement of the historic period, as appears by the following passages from Herodotus. Speaking of the people who inhabited some small islands on the river Araxes, which flows into the Caspian Sea, he says,[^[22]] “They add that they have discovered other trees that produce fruit of a peculiar kind, which the inhabitants, when they meet together in companies, and have lit a fire, throw on the fire as they sit round in a circle; and that by inhaling the fumes of the burning fruit that has been thrown on, they become intoxicated by the odour, just as the Greeks do by wine; and that the more fruit is thrown on, the more intoxicated they become, until they rise up to dance and betake themselves to singing.”

Again, when treating of the funeral ceremonies of the Scythians, he says,[^[23]] “When they have set up three pieces of wood, leaning against each other, they extend round them woollen cloths; and having joined them together as closely as possible, they throw red-hot stones into a vessel placed in the middle of the pieces of wood and the cloths. They have a sort of hemp growing in this country very like flax, except in thickness and height; in this respect the hemp is far superior: it grows both spontaneously and from cultivation; and from it the Thracians make garments very like linen, nor would any one who is not well skilled in such matters distinguish whether they are made of flax or hemp, but a person who has never seen this hemp would think the garment was made of flax. When, therefore, the Scythians have taken some seed of this hemp, they creep under the cloths, and then put the seed on the red-hot stones; but this, being put on, smokes, and produces such a steam, that no Grecian vapour-bath would surpass it. The Scythians, transported with the vapour, shout aloud; and this serves them instead of washing, for they never bathe the body in water.”

Mental illusions of all kinds have frequently been looked on as divine revelations, not only by savages, but even by nations having a considerable amount of civilization. The priestess at Delphos became intoxicated with the fumes of narcotic plants before delivering her oracular responses, and it is a curious circumstance that when America was discovered by Columbus, it was the custom of the Indians to throw tobacco on the fire during their religious ceremonies, when the piaches, or priests, who officiated, were thrown into a state of ecstatic inebriation by the smoke they inhaled.

I have already stated my belief that the Indian hemp administered, previous to surgical operations, in China, by Hoa-tho, in the beginning of the third century of our era, was exhibited by inhalation.

The fumes of various narcotic plants are inhaled by eastern nations at present, for smoking in the east is an entirely different process from smoking in the west of Europe, where the fumes of tobacco are merely drawn into the mouth and then puffed out again. In Asia and some of the eastern parts of Europe, the fumes of opium, tobacco, datura, Indian hemp, or whatever else is smoked, are always inhaled into the lungs.

John Baptista Porta of Naples makes the following statement in his work on Natural Magic,[^[24]] published in 1597:—

“At last shall be related a wonderful method by which any sleeping person may inhale a soporific medicine. From what we have said, any one will easily know that he is liable to suffer severely after sleep caused by medicine, and to have his suspicions aroused.

“But the quintessence is extracted from a number of the above named medicines by somniferous menstrua. This is put into leaden vessels perfectly closed, lest the least aura should escape, for the medicine would vanish away. When it is used, the cover being removed, it is applied to the nostrils of the sleeping person, he draws in the most subtile power of the vapour by smellings, and so blocks up the fortress of the senses that he is plunged into the most profound sleep, and cannot be roused without the greatest effort. After the sleep, no heaviness of the head remains, nor any suspicion of trick or fraud. These things are plain to the skilful physician, but unintelligible to the wicked.”

The author does not make known what the “somniferis menstruis” were, with which the “quinta essentia” were extracted. As sulphuric ether had been described more than fifty years before he published his work, it is not improbable that this was the evanescent substance which required to be so carefully closed up, and that the profound sleep was simply caused by this, as the narcotic principles dissolved in it would remain in the bottle in the form of extracts. The benefit of inhalation has been frequently attributed to medicines which were supposed to be inhaled, when it was really due to the menstruum in which the medicines were dissolved. This often happens at present when the menstruum is merely water. Baptista Porta does not say that operations were performed under the influence of the inhalation, or, in fact, that it was applied to any useful purpose whatever.

The Persian Pharmacopœia[^[25]] contains some recipes for fumigation, called bouc-houri, that were inhaled, for the medicines are directed to be made up into balls or cubes which are to be placed on the live coals, and the head is to be held over them. Some of the prescriptions contain myrrh, camphor, mace, and storax, and are for the cure of coryza and catarrh; one containing musk, camphor, guaiacum, etc., is said to comfort the brain and intellect, and to be useful in palpitation of the heart, faintness, and debility of the senses. This Pharmacopœia also contains[^[26]] a “remedium odorativum somniferum”, which consists of opium and camphor, besides the seeds of roses and the root of mandragora. The ingredients are to be powdered and put in a box, for the purpose of being smelt at. There is also[^[27]] a stupifying remedy prepared with five drachms of opium and ten drachms of black poppy, which are directed to be boiled to dryness in water with a pound of wheat, and then powdered. It is added that whoever shall take a drachm and a half of this wheat will be alienated from his senses. With regard to the last but one of the above prescriptions—that to be put in a box for smelling, it may be observed that, as heat was not applied, the only ingredient which would produce any effect is the camphor.

The discoveries of Cavendish, Priestley, Lavoisier, and others respecting the nature of atmospheric air and the more important gases, gave an impetus to medicinal inhalations, at the latter part of the last century. Dr. Beddoes, in particular, distinguished himself by the administration of oxygen, hydrogen, carbonic acid, and other gases, in consumption and various diseases. Dr. Richard Pearson exhibited the vapour of ether in consumption with some advantage in the year 1795.[^[28]] Three years afterwards, a medical pneumatic institution was established at Bristol, by the exertions of Dr. Beddoes and others. The celebrated Humphrey Davy was the superintendent. This establishment was not very successful in the immediate objects for which it was instituted, but Davy made at this place his masterly researches concerning nitrous oxide gas. In the course of his experiments, he found that severe pain arising from inflammation of his gums was relieved by breathing this gas, and he published the following opinion:—

“As nitrous oxide in its extensive operation seems capable of destroying physical pain, it may probably be used with advantage during surgical operations in which no great effusion of blood takes place.”[^[29]]

This suggestion of Sir Humphrey Davy was not acted on either by himself or any other person for nearly half a century, when the late Mr. Horace Wells, Surgeon Dentist of Hartford, Connecticut, having witnessed the exhibition of nitrous oxide gas by a public lecturer, named G. Q. Colston, was induced, in consequence of what he saw of its effects, to request Mr. Colston to accompany him to his office and exhibit the gas to him, whilst another dentist, named Dr. Riggs, extracted a tooth for him which was troublesome. The tooth was extracted without pain, and Mr. Wells, after the effect of the gas had subsided, exclaimed, “A new era in tooth pulling.” This took place on December 11th, 1844.[^[30]] Mr. Wells administered the nitrous oxide in thirteen or fourteen cases of tooth-drawing in Hartford with a success more or less complete, and before the end of the year he repaired to Boston to introduce his discovery to the professors at the Massachusetts General Hospital. He called on Drs. Warren and Hayward, who invited him to exhibit the gas to one of the patients, who was expecting to have a limb amputated. He remained two or three days in Boston, but the patient decided not to have the operation performed at that time. The nitrous oxide was consequently tried on an individual who required to have a tooth extracted. This patient felt some pain, and the application was considered to be a failure. It is worthy of remark that Drs. Charles T. Jackson, and W. T. G. Morton, were present on this occasion. Mr. Wells returned to Hartford in disappointment. He expressed his opinion to his friends that the nitrous oxide gas was uncertain in its action, and not to be relied on; and he altogether abandoned the use of it until some time after Dr. Morton’s discovery of the effects of sulphuric ether in preventing pain.

As long ago as 1818 an article, which is believed to have been written by Mr. Faraday, appeared in the Quarterly Journal of Science and Arts,[^[31]] describing the great resemblance between the effects of the vapour of ether and nitrous oxide gas. This circumstance has since been published in all the standard works on chemistry; and it was the annual custom of the late Professor Turner, of University College, London, to pour a little ether into a bladder of air, and allow some of the students to inhale the vapour. The same practice prevailed, more or less, in other colleges, both in Europe and America, when the lecture on ether was delivered. The resemblance between the action of nitrous oxide and that of vapour of ether was therefore extensively known.

Dr. Morton, surgeon dentist of Boston, in America, administered sulphuric ether, by inhalation, to a man in his office, on the 30th of September, 1846, and extracted a tooth without causing any pain. He applied the ether in several cases of a similar kind during the next few days. Having obtained the permission of Dr. J. C. Warren, he administered it to a patient in the Massachusetts General Hospital, on whom that surgeon performed an operation on the neck. On the following day, Dr. Morton exhibited ether to a woman in the same hospital, whilst Dr. Hayward removed a large fatty tumour from the arm, and after this date it was frequently administered.

Dr. Morton was well acquainted with Mr. Horace Wells, before alluded to, and had been in partnership with him. Before administering the ether to his patient in September 30th, Dr. Morton had a conversation with Dr. Charles J. Jackson, Professor of Chemistry, respecting the safety and propriety of the application, and the names of these gentlemen were associated in a patent which they took out for the discovery. Dr. Jackson asserts that Dr. Morton knew nothing of the effects of the vapour of ether till he gave him the information; whilst the latter says it was his intention to use the ether before he went into Dr. Jackson’s laboratory. It seems impossible to arrive at the exact truth on this point, but it is admitted on all hands, that Morton was the first who administered ether to prevent the pain of an operation. Dr. Jackson[^[32]] has indeed claimed the whole merit of the discovery, on the ground of the alleged information he gave to Dr. Morton; but, if every word Dr. Jackson says be admitted, it only appears that he suggested the use of ether to Dr. Morton, just as Sir Humphrey Davy had suggested the use of nitrous oxide to all the world in the year 1800. Dr. Jackson had inhaled ether as hundreds of others had done, and being aware of Davy’s suggestion of nitrous oxide for preventing the pain of operations, he concluded that ether might also have that effect.

It will be shown further on that Mr. Waldie, of Liverpool, had a greater share in the introduction of chloroform than Dr. Jackson had in the introduction of ether—even supposing that Dr. Morton was previously quite ignorant of that medicine; for when he informed Dr. Simpson of the existence and nature of chloroform, he was able to give him, not merely an opinion, but an almost certain knowledge of its effects; yet Dr. Simpson is justly considered to be the person who discovered and introduced the use of undiluted chloroform as a substitute for ether.

The practice of the ancients in giving mandragora and Indian hemp has no connection with the recent discovery for preventing the pain of operations, which may be briefly related as follows:—Sir Humphrey Davy made the suggestion that nitrous oxide gas might be employed for this purpose, and, at the end of forty-four years, Mr. Horace Wells carried this suggestion into practice, but failed to bring the nitrous oxide into general use, and gave the matter up. Two years later, Dr. Morton, who was well acquainted with the efforts of Mr. Wells, applied the vapour of ether, which was already known to resemble nitrous oxide in its action. He succeeded completely in preventing the pain of operations, and in bringing his discovery into general use throughout the civilized world. In a short time the inhalation of ether was found to be so safe and certain in its action, and to prevent the pain of operations so entirely, that the most ardent imagination could scarcely conceive that anything further could be desired in this direction.

Dr. Morton withheld at first the name of the agent he was employing, but its strong and peculiar odour revealed it so plainly that concealment was impossible. Dr. Bigelow, of Boston, having tried sulphuric ether, and found it to produce all the effects of the so-called letheon, he made the subject known, not only to his own countrymen, but also by letter to Dr. Boot of London. The first operation under the influence of ether on this side of the Atlantic, was the extraction of a tooth, at the house of Dr. Boot, on Dec. 19th, 1846. Mr. Robinson, of Gower Street, administered the ether and performed the operation. The patient was a lady, named Miss Lonsdale. The ether was quite successful in preventing the pain in this case, as well as in two operations performed at University College two days afterwards, by the late Mr. Liston. These operations were amputation of the thigh, and evulsion on both sides of the great toe-nail. The ether was given by Mr. Squire, of Oxford Street, with an apparatus which he contrived for the occasion.

Considerable opposition was made to the inhalation of ether in America, soon after its introduction, and it seemed likely to fall into disuse, when the news of its successful employment in the operations of Mr. Liston, and others in London, caused the practice of etherization to revive. Mr. Robinson, dentist, gave much time and attention to the exhibition of ether in London on its first introduction, and was on the whole very successful. This was not generally the case, however, with other operators during the first six weeks of the new practice. Owing to imperfections in the inhalers employed and in the method of using them, the ether often either failed altogether or only made the patient partly insensible; and Mr. Liston, and some other surgeons, were inclined to discountenance the use of it, in consequence of the struggles and cries of patients to whom it had been administered.

It soon became apparent, however, that the vapour of ether was capable of inducing a state of perfect quietude, with entire absence of pain, during all kinds of surgical operations. From the 28th of January the ether produced the desired effect in every operation that was performed in St. George’s Hospital, until the time when chloroform was introduced as a substitute for this agent.[^[33]]

Ether was employed in Paris a few days after its first application in London, and in a short time it was in use nearly all over the world.

On the 19th of January 1847, just a month after the first application of ether for the prevention of pain on this side of the Atlantic, Dr. Simpson of Edinburgh administered the vapour in a case of labour, and ascertained that it was capable of removing the sufferings of the patient without interfering with the process of parturition. Etherization was soon afterwards employed in the reduction of strangulated hernia and dislocations of the femur and humerus, some of them of long standing. It was also used with advantage in neuralgia, tetanus, and the convulsions of infants, and it became more and more general in surgical operations.

No great improvement in the practice of medicine was probably ever established so readily as the inhalation of ether for the prevention of pain. Yet it met with stout opposition in certain quarters, and when a serious operation in which ether had been used terminated unfavourably, there were those who attributed the patient’s death to the new practice, although numerous other patients had sunk in exactly the same manner long before ether was used. In one of these cases a coroner’s inquest was held, and the jury returned a verdict that the death of the deceased was caused by the inhalation of ether, although the patient had not even been made insensible by it, had felt all the pain of the operation, which was retarded by her struggles, and did not die till the third day. Notwithstanding a certain amount of opposition and mistrust, the inhalation of ether was becoming more general in the course of the year 1847, and there is every reason to conclude that it would very soon have obtained the complete confidence of the medical profession and the public, had it not been for circumstances which must next be considered.

A medicine called chloric ether has been in use since 1831. It consists of a solution of chloroform in spirits of wine. It is somewhat variable in strength, but usually contains about twelve per cent. of its volume of chloroform. Dr. Henry Jacob Bigelow of Boston tried this by inhalation, as well as other substances, when Dr. Morton first used sulphuric ether, but he did not succeed with it in causing insensibility to pain. Mr. Jacob Bell of London tried the chloric ether in the beginning of 1847, and succeeded in causing insensibility with it in some cases.[^[34]] After this time the chloric ether was exhibited occasionally in St. Bartholomew’s and the Middlesex hospitals, and in the private practice of Mr. Lawrence, but it did not come into general use, owing to its expense, and its frequently failing to cause insensibility.

The relation of chloroform to chloric ether is exactly the same as that of opium to laudanum, and no one acquainted with this circumstance could doubt for a moment that chloroform inhaled alone would produce the effects which it did when inhaled from its solution in spirit; the only uncertainty about the matter that could possibly exist would be whether it might not be too strong for use in its undiluted state.

The true nature of the so-called chloric ether was, however, known to very few persons. It did not enter into the pharmacopœias, and it was mentioned in very few of the works on materia medica. I examined a specimen of it, and found that its properties when inhaled were due to a volatile body containing chlorine, which evaporated first, leaving a great quantity of spirits of wine behind. I concluded that the volatile body was hydrochloric ether, and as this article is so volatile that it exists in the form of gas except in comparatively cold weather, and consequently could not be conveniently used for inhalation, I did not consider the matter any further. M. Flourens had indeed experimented on animals with undiluted chloroform, but was so struck with its great and dangerous power, that he was far from recommending its use in surgical practice.

It was left for Dr. Simpson of Edinburgh, who had already the merit of having discovered the use of inhalation in midwifery, to be the first to administer chloroform in an undiluted state, and to recommend it successfully for general use. Mr. Waldie, of the Apothecaries’ Hall of Liverpool, first mentioned chloroform to Dr. Simpson, as the latter states in a foot-note to his first pamphlet on the subject. Mr. Waldie has given the following account of the circumstance in a pamphlet on chloroform.[^[35]]

“When in Scotland, in October last, Dr. Simpson introduced the subject to me, inquiring if I knew anything likely to answer. Chloric ether was mentioned during the conversation; and, being well acquainted with its composition, and with the volatility, agreeable flavour, and medicinal properties of the chloroform, I recommended him to try it, promising to prepare some after my return to Liverpool, and to send it to him. Other engagements and various impediments prevented me from doing this so soon as I should have wished; and in the meantime Dr. Simpson, having procured some in Edinburgh, obtained the results which he communicated to the Medico-Chirurgical Society of Edinburgh on the 10th of November, and which he published in a pamphlet entitled—‘Notice of a New Anæsthetic Agent as a Substitute for Sulphuric Ether in Surgery and Midwifery.’”

Dr. Simpson’s first experiments with chloroform were made in the early part of November 1847, and his pamphlet on the subject, which was published on the 15th of that month, had a wide circulation, and created great interest. Chloroform was immediately used everywhere to a greater extent than ether had been. An impression became very prevalent that chloroform was safer than ether. This impression arose rather from the general tenour of Dr. Simpson’s essay than from any direct statement, for he had not treated on this point.

The great strength of chloroform as compared with ether, and the extreme care required in its use, were indeed soon pointed out;[^[36]] these precautions, however, attracted but little attention till the first death from chloroform occurred near Newcastle on the 28th January, 1848. Ether was exhibited by inhalation during eleven months in Europe, and about sixteen months in America, before chloroform was introduced. During all this time no death was occasioned by its use, if we except one at Auxerre in France, which appeared to be occasioned by want of air, owing to an imperfect inhaler, and not to the effect of ether. Chloroform had only been employed between two and three months when the above mentioned death occurred, and this was soon followed by others in nearly all parts of the world. These accidents have prevented many persons from inhaling chloroform, and they have prevented a still greater number from enjoying that freedom from anxiety and apprehension before an operation, which ought to be one of the greatest advantages of any plan for preventing pain. As chloroform possesses advantages over ether, in being more convenient and less disagreeable, it continues to be used, to the exclusion of the latter agent, in most parts of the world. In the Massachusetts General Hospital, however, where sulphuric ether was first employed, it was resumed three or four years ago, and the use of chloroform was prohibited by the governors, on account of two accidents from it. Ether is also employed out of the hospital, both in surgical and obstetric practice, in Boston and the neighbourhood; and I have been informed that this is also the case in Philadelphia, whilst in the state of New York both chloroform and ether are employed. I learned last year that ether was the agent employed for causing insensibility at Naples and at Lyons.

Several volatile substances have been tried in a few cases with the effect of causing insensibility, since the introduction of chloroform, but none of them came into use except amylene, which was first employed by me in King’s College Hospital in November 1856, after I had made several experiments on animals with it, and inhaled small quantities of it myself. I have administered it in a great number of operations already, and find it to possess certain advantages over chloroform in the greater number of cases. Although it has not yet been generally employed in this country, it has been used extensively in Paris, Strasbourg, Lyons, and other places on the continent, with very favourable results.

It is not improbable that, amongst the multitudes of new bodies which chemistry makes known every year, some agent may be found superior to those hitherto used; and besides the great practical advantages which are directly derived from the discovery of inhalation for the prevention of pain, the method of breathing medicinal substances in the gaseous state offers great facilities for the investigation of their effects, and cannot fail to hasten the time when the mode of action of medicines will be a branch of exact knowledge.

ON THE
INHALATION OF CHLOROFORM, ETC.

GENERAL REMARKS ON INHALATION.

Inhalation is simply the act of breathing, or at least so much of it as consists of inspiring, or drawing the air into the lungs. The term is usually applied when any medicinal substance is added to the air which the patient breathes, and the process is altogether different from that called “smoking,” as practised by the nations of western Europe and of America, where the fumes of tobacco are merely drawn into the mouth and puffed out again. The eastern nations, however, always inhale when they smoke, as was stated before (page 12). This process of inhaling smoke, as I first witnessed it in a gentleman connected with one of the eastern embassies to this metropolis, is very instructive, as showing that the lungs become emptied of their contents by three rather full expirations and inspirations. When this gentleman took the cigar from his mouth to speak, the smoke could be seen issuing thickly with each word till there was a momentary pause as he took a fresh inspiration, then the smoke could be seen issuing with each word as before, only not so thick, and after another inspiration, the smoke could be still perceived in the expired air, but in a very diluted state; but after a third inspiration, it could no longer be seen till he had resumed the cigar.

The following are the chief reasons for resorting to inhalation.

1. Certain agents, as nitrous oxide and oxygen, being permanently in the gaseous form, cannot be administered in any other way.

2. By taking advantage of the immense surface of the air-cells of the lungs for absorption, a more sudden and profound effect may be produced by medicine than it would be safe, or, in some cases, even possible to produce in any other way. It is to this circumstance, and to the rapidity with which certain volatile medicines exhale in the breath, and leave the patient free from their effects, that the power of preventing the pain of surgical operations is due.

3. Many medicines which have a disagreeable taste—as turpentine, creasote, and camphor—are not unpleasant when inhaled in the form of vapour; and the process of digestion is less interfered with than by taking them into the stomach.

4. Medicines, such as benzoic acid, and some of the gum-resins, which are believed to exert a local action on the mucous membrane of the air-passages, may be expected to have a greater effect when inhaled, than when they are taken into the stomach in the same doses, and reach the lungs only through the circulation.

5. Some agents, as chlorine and ammonia, have a local action when inhaled, which they could not exert if exhibited in any other way.

In every kind of inhalation, the breathing should be allowed to go on freely, and in the natural way.

Medicines may be inhaled either at the ordinary temperature, or with the aid of artificial heat; and in the latter case they may be breathed with the addition of vapour of water, or with only so much of it as is naturally present in the atmosphere. The medicines in use for the prevention of severe pain, are always inhaled at the ordinary temperature.

CHLOROFORM.

History and Composition. Chloroform was first made in 1831 by two chemists who operated independently of each other. The liquid, which is formed by the union of equal volumes of chlorine and olefiant gas, and which is usually called Dutch liquid, was named chloric ether by Dr. Thos. Thomson (System of Chemistry, 6th ed., 1820). In consequence of a statement in Silliman’s Elements of Chemistry, that the alcoholic solution of this chloric ether was useful in medicine as a diffusible stimulant, Mr. Guthrie, an American chemist, attempted an easy method of obtaining it.[^[37]] He distilled together chloride of lime and alcohol, and he considered that the product he had obtained was an alcoholic solution of the chloric ether of Dr. Thomson,[^[38]] and it is still used in medicine under that name. About the same time, M. Soubeiran distilled together the above ingredients in France, and analysed the chloroform which he obtained. His analysis, which was incorrect, led him to name the liquid bichloric ether.[^[39]] In 1832, Liebig examined the liquid which has been since named chloroform, but as he failed to detect the hydrogen which it contains, he called the liquid chloride of carbon,[^[40]] a name which its alcoholic solution occasionally bore afterwards when used as a medicine. In 1831, Dumas examined this liquid. He proved that Soubeiran and Liebig had not obtained it pure, or had been incorrect in their analysis.[^[41]] He showed that it consists of two atoms carbon, one atom hydrogen, and three atoms chlorine.

Dumas gave the name of chloroform to the liquid, on account of the relation it bears in composition to formic acid, which consists of two atoms carbon, one hydrogen, and three oxygen.[^[42]] Liebig, who, in common with other chemists, admits the accuracy of Dumas’ analysis, has proposed the name of perchloride of formyle.[^[43]] He supposes that the carbon and hydrogen which enter, in the same definite proportion, into numerous compounds, form a base which he calls formyle; and although this base has never been obtained in a separate form, its existence is well supported by analogy, and the term formyle is useful in assisting the memory to retain the composition of a number of substances. For all practical purposes, however, the medicine we are considering is likely to go by the name of chloroform. In the last edition of the London Pharmacopœia, the article has received a name intermediate between the other two. It is called chloroformyl, a name which departs from the brevity of the word chloroform, without having the merit of expressing the chemical constitution of the substance. I believe that no one uses the word chloroformyl; not even the Fellows of the College of Physicians in their individual capacity.

Mode of Preparation. Chloroform can be obtained in various ways, but the most convenient process, and the one which yields it in greatest purity, is that alluded to above, by which it was first procured. The following are the directions in the London Pharmacopœia for making it.

“Take of chlorinated lime, lb. iv; rectified spirit, Oss; water, Ox; chloride of calcium, broken in pieces, ʒj. Put the lime first mixed with the water into a retort, and add the spirit to them, so that the mixture may fill only the third part of the retort. Then heat them in a sand-bath, and as soon as ebullition begins, withdraw the heat as quickly as possible, lest the retort should be broken by the sudden increase of heat. Let the liquid distil into the receiver so long that there may be nothing which subsides, the heat being reapplied if necessary. To the distilled liquid add a quarter of the water, and shake them all well together. Carefully separate the heavier portion which subsides, and add the chloride to it, and frequently shake them for an hour. Lastly, let the liquid distil again from a glass retort into a glass receiver.”[^[44]]

Some manufacturers of chloroform prefer to rectify it from dry carbonate of potassa, since they consider that it is liable to get an acid reaction from decomposition of the chloride of calcium, when it is distilled from that substance. The truth is, however, that there is very little occasion to use either of these substances; for the small quantity of water which chloroform can hold in solution is of no consequence.

Chemical and Physical Properties. Chloroform is a clear colourless liquid, having a hot and intensely sweet taste. It is not inflammable, but when paper moistened with it is introduced into the flame of a candle, it is destroyed with the evolution of smoke and chlorine gas. It is just half as heavy again as distilled water. Its specific gravity was formerly stated to be 1·483, but the liquid used for inhalation of late years has been heavier than this. I find that pure chloroform, when saturated with water, has a specific gravity of 1·500 at 60° Fah.; and after agitating it with sulphuric acid, to deprive it of the water, the specific gravity is 1·503. The amount of water that chloroform can hold in solution is only one part in from 200 to 300; and when this is separated by oil of vitriol, the chloroform is liable to undergo spontaneous decomposition.[^[45]]

Chloroform is soluble in alcohol and ether in all proportions, but it is very sparingly soluble in water. It has been said to require 2000 parts of water for its solution, but this is an error. As the solubility of this and similar medicines in watery fluids has a very important connexion with their physiological action, I took great pains to ascertain the solubility of chloroform correctly. By admitting small quantities of water into graduated jars containing chloroform vapour, I was able to ascertain that chloroform is soluble in about 288 times its volume of water. Chloroform is itself an active solvent of many bodies; dissolving camphor, caoutchouc, gutta percha, wax, resin, iodine, and some other substances very readily. It is a very mobile liquid, and when dropped from the lip of a small phial, the drops are very small. There are three drops to a grain of the liquid, and as a minim of it weighs a grain and a half, there are nine drops in two minims. Consequently persons should not speak indiscriminately of drops and minims, as they sometimes do, when talking of chloroform.

Adulterations. The odour of chloroform is by no means disagreeable. The only liquids that resemble it in smell are Dutch liquid and the chlorinated products of hydrochloric ether, but as they are much more difficult to prepare than chloroform, they are not likely to be substituted for it, or used for its adulteration. The smell of chloroform is therefore a good criterion of its purity and identity. When dropped on the hand, it should quickly evaporate, leaving not the least moisture or smell behind. If a disagreeable odour remains on the hand after the evaporation of the chloroform, it has probably been made from impure spirit, or even from wood spirit or acetone, and is unfit for medicinal use.[^[46]] When chloroform becomes decomposed from any cause, it acquires a greenish-yellow colour, and gives off chlorine and hydrochloric acid, so that the alteration is at once apparent. When chloroform is pure it has no reaction on test-paper, but is quite neutral. The best way to detect a small quantity of hydrochloric acid in it, is to moisten a slip of blue litmus paper with distilled water, and hold it just within the neck of the bottle exposed to the vapour. If sulphuric acid should be present, it may be discovered by agitating the chloroform with distilled water, and adding nitrate of baryta.

The only article that can be mixed with chloroform without altering its appearance and smell is alcohol. This can be detected by the reduction it occasions in the specific gravity of the chloroform; or, if it be present in any considerable quantity, it may be discovered by adding water to a little of the chloroform in a graduated tube or measure, when a diminution of its volume takes place, owing to the water abstracting the alcohol. The chloroform also acquires a milky opacity under these circumstances. M. Miahle[^[47]] speaks of the milky opacity of the chloroform on the addition of water as a very delicate test of the presence of alcohol; but I find that it requires upwards of two per cent. of alcohol to cause this appearance on the addition of water.

It has been asserted, and often repeated, that the presence of alcohol in chloroform causes it to have caustic properties, and makes its vapour unusually irritating. I have never seen any evidence of this, although I have had hundreds of opportunities of witnessing the action of chloroform mixed with spirit. Under certain circumstances, it is advisable to dilute chloroform with alcohol previous to its administration, as will be explained hereafter.

The chloroform I have met with in London has always been sufficiently pure for inhalation, except in a few cases where a small quantity had become decomposed, probably from having been left a long time exposed to strong daylight. In these instances, its altered appearance generally prevented its being used. I am not aware of serious consequences having arisen anywhere from the impurity or adulteration of chloroform. A case occurred in the London Hospital, where cough and a feeling of suffocation were caused by hydrochloric acid with which the chloroform was contaminated, but the inhalation was discontinued, and no ill consequences resulted.[^[48]]

Chloroform should be kept in well-stoppered bottles, and protected from the light. It boils at 140 Fah. under the ordinary pressure of the atmosphere. It is consequently one of the most volatile liquids employed in medicine, with the exception of sulphuric ether and amylene.

The Vapour of Chloroform is more than four times as heavy as atmospheric air. It has a specific gravity of 4·2 at 60° Fah. Under ordinary circumstances, the vapour of chloroform has of course no separate existence, but is always mixed with air. It can exist in a pure state only when the temperature is raised to 140° or upwards; or when the pressure of the atmosphere is in a great measure removed by the air-pump. The quantity of vapour of chloroform that the air will hold in solution at different temperatures, under the ordinary pressure of the atmosphere, depends on the elastic force of the vapour at these temperatures. It is governed by a law precisely analogous to that which determines the amount of watery vapour which air will hold in solution.

The following table shows the result of experiments I made to determine the quantity of vapour of chloroform that 100 cubic inches of air will take up, and retain in solution, at various temperatures.

In the above table, the air is a constant quantity of 100 cubic inches which becomes expanded to 107, and so on; but it may be convenient to be able to view at a glance the quantity of vapour in 100 cubic inches of the saturated mixture of vapour and air, at different temperatures, and in the table which follows the figures are so arranged as to show this.

As the effects of chloroform when inhaled depend entirely on the quantity of vapour present in the air which the patient breathes, the effect of temperature on its volatility is of great practical importance. The air, it is true, does not become fully saturated with vapour during the process of inhalation, but the effects of temperature are relatively as great. If, for instance, a person inhales chloroform from a handkerchief or an inhaler, in such a way that the air he breathes shall be half saturated with the vapour, then supposing the temperature of the apartment, the handkerchief, etc., to be 50°, the air he breathes will contain 4 per cent.; but if the temperature be 70°, the air will contain 9·5 per cent. of the vapour.

A considerable amount of caloric becomes latent during the evaporation of chloroform, and the temperature of the vapour and air which the patient breathes are generally reduced a good deal, but not to the same extent as during the inhalation of ether. In giving chloroform from a small sponge which had been squeezed out of water, I have sometimes observed, after laying it down, that it became covered with a kind of hoar frost; the minute particles of frozen water having a slight taste of chloroform. The cold produced by the evaporation of a liquid like chloroform is often the means of checking the evaporation to a certain extent, and limiting the amount of vapour which is taken up by the air.

PHYSIOLOGICAL EFFECTS OF CHLOROFORM.

Chloroform belongs to the large class of medicines known as narcotico-irritants. This and some other agents which have been inhaled for the prevention of pain are often called anæsthetics; a name to which there is no objection, so long as it does not lead to the idea that they have a different action from other narcotics, or more precisely speaking, narcotico-irritants; there being no such medicines as pure narcotics. The term anæsthesia has been frequently employed to designate the insensibility and suspension of consciousness caused by chloroform and ether; but, in describing the effects of these agents, I shall confine this term to its original meaning, privation of feeling, and I shall employ the term narcotism to designate the entire effects of these agents on the nervous system. This is the sense in which the term narcotism has always been employed. It has been the custom, however, to restrict the use of the word very much to cases in which stupor existed, but I shall apply it to designate the slighter, as well as the more profound effects of a narcotic, as I am entitled to do by strict etymology.

In order to facilitate the description of the effects of chloroform, I have been in the habit of dividing them into degrees. I use the term degree in preference to stage, as, in administering chloroform, the slighter degrees of narcotism occur in the later stages of the process, during the recovery of the patient, as well as in the beginning. The division into degrees is made according to symptoms, which, I believe, depend entirely on the state of the nervous centres, and not according to the amount of anæsthesia, which there is good reason to conclude, depends, in a great measure, on the local action of the chloroform on the nerves. The different degrees of narcotism glide insensibly into each other.

In the first degree, I include all the effects of chloroform that exist while the patient retains a perfect consciousness of where he is, and what is occurring around him. This degree constitutes all that a person remembers of the effects of the vapour, except when he happens to dream, and recollect it afterwards. The sensations caused by inhaling chloroform are usually agreeable, when it is taken merely for curiosity; and individuals who have inhaled nitrous oxide at some previous time of their lives, often describe their feelings as being very much the same from both agents. Patients who are about to undergo a surgical operation are, however, not always in a state for receiving agreeable impressions, and they sometimes complain of palpitation of the heart, and a feeling of fulness in the head. There is generally a sense of dizziness, with singing in the ears and tingling in the limbs. Many persons have a feeling like that of rapid travelling, and as an appearance of darkness sometimes comes on from the failure of the sight, whilst there is also a loud noise in the ears, it not unfrequently happens that a person feels as if he were entering a railway tunnel, just when he is becoming unconscious.

Those persons whose mental faculties are most cultivated appear usually to retain their consciousness longest whilst inhaling chloroform; and, on the other hand, certain navigators and other labourers, whom one occasionally meets with in the hospital, having the smallest possible amount of intelligence, often lose their consciousness, and get into a riotous drunken condition, almost as soon as they have begun to inhale. There is a widely different class of persons who also yield up their consciousness very readily, and get very soon into a dreaming condition when inhaling chloroform. I allude to hysterical females.

There is often a considerable diminution of the common sensibility during the first degree of narcotism by chloroform, more especially when it is inhaled very slowly, so that the patient is kept some minutes partially under its influence. In this way neuralgia can often be relieved, without removing the consciousness, when it is not extremely severe, and the suffering of labour may often be removed in the same manner, when the pains are not very sharp. In a few cases, the extraction of a tooth and other minor operations have been performed without pain, whilst consciousness has been retained; but as a general rule, it is better not to operate under these circumstances, for failure is more likely than success; and this plan does not succeed in any case without inhaling longer, and consuming more chloroform, than would be necessary in the usual way. The complete recovery of the patient from the effects of the vapour, after a protracted inhalation of this kind, is also more tardy.

The first degree of narcotism recurs when consciousness returns as the effect of the chloroform is subsiding. At this time, there is generally a greater amount of anæsthesia than at the commencement of inhalation, just before consciousness is removed. I have many times known the introduction of sutures, and such like measures, performed at the concluding part of an operation, after the patient had recovered his consciousness, without his feeling what was being done. As a general rule also, the smarting of the wound does not commence till some time after consciousness has returned.

In the second degree of narcotism, there is no longer correct consciousness. The mental functions are impaired, but not necessarily suspended. When a patient inhales chloroform quietly for a medical or surgical purpose, he usually appears as if asleep in this degree; but if his eyelid be raised, he will move his eyes in a voluntary manner. There are occasionally voluntary movements of the limbs; and although the patient is generally silent, he may nevertheless laugh, talk, or sing. Persons sometimes remember what occurs whilst they are in this state, but generally they do not. Any dreams that the patient has, occur whilst he is in this degree, or just going into, or emerging from it, as I have satisfied myself by comparing the expressions of patients with what they have related afterwards. There is sometimes a little trouble with the patient in this degree of narcotism. He feels the inconvenience of the vapour he is breathing, and having become unconscious of the object for which it is inhaled, he endeavours to push away the inhaler. As a person in this condition can generally hear and partly understand what is said, a few kind words will often render him tractable. This is generally true of all those who have been brought up with care and kindness, more especially patients of the female sex; but the man who has been roughly treated from the time of his birth, can often be made insensible only by means of a little restraint.

There is generally a considerable amount of anæsthesia connected with this degree of narcotism, and I believe that it is scarcely ever necessary to proceed beyond it in obstetric practice, not even in artificial delivery, unless for the purpose of arresting powerful uterine action, in order to facilitate turning the fœtus. The loss of sensation is indeed sometimes so complete in this degree, especially in children, that the surgeon’s knife may be used without pain; I have indeed seen a child unconsciously handling its toys all the time that the operation of lithotomy was performed on it. Commonly, however, the use of the knife, when the narcotism has not proceeded further than this degree, occasions expressions indicative of pain, which are either not remembered, or are recollected as having occurred in a dream. The patient is generally in this degree during the greater part of the time occupied in protracted operations; for although, in most cases, it is necessary to induce a further amount of narcotism before the operation is commenced, it is not usually necessary to maintain it at a point beyond this.

In the third degree of narcotism, there are no longer any voluntary motions. The eyes, for instance, are not directed towards any object; and although the limbs may move, they are not directed to any purpose. The pupils are generally inclined upwards in this degree, and are at the same time usually somewhat contracted. The bloodvessels of the conjunctiva are generally somewhat enlarged in this degree in all persons who are well nourished and not deficient in blood. It is in this degree of narcotism that rigidity and spasms of the muscles occur in certain cases. These phenomena occur most frequently in cases where the muscles have been much exercised, and are consequently well nourished. They are never met with in infancy, and rarely before puberty. They are much more common in the male than the female sex. The rigidity and spasm are greatest and most constant in labourers and persons accustomed to athletic exercises, and they are usually absent in patients who have been long confined to the room, or are much reduced in strength from any cause. They are less marked in old age than in the middle period of life, and they are not by any means so frequent or strong in fat, as in thin, muscular persons. I have seen the spasms take an epileptiform character in a few cases; but by gently continuing the chloroform, they have always been subdued. In a great number of cases, the patient mutters in an almost inarticulate and a perfectly unintelligible manner, just as the muscular rigidity and spasm are subdued. Under these circumstances, I have never heard a single word pronounced so that it could be understood. If articulate language is uttered just after the muscular rigidity, it is evidence that the effects of the chloroform are being allowed to diminish, and that the patient is going back into the second degree of narcotism.

In the third degree of narcotism, a person is quite incapable of having any perception or consciousness of pain, but anæsthesia is not a necessary part of this amount of narcotism when it is first induced, and in some cases a patient may flinch, and put on an expression of countenance which seems indicative of pain. He may also cry out, but not in an articulate manner. By continuing the chloroform gently for a minute or so, a state of complete anæsthesia can be induced in nearly every case, without carrying the narcotism of the nervous centres further than this degree. The loss of sensibility of the conjunctiva, as shown by the absence of winking when the edges of the eyelids are gently touched, is the best criterion that the patient will bear the knife without flinching or crying.

The circumstance of the anæsthesia, or loss of common sensibility, not keeping pace with the degree of narcotism of the brain, as shown by the presence or absence of consciousness and volition, appears to depend on the chloroform acting on the peripheral distribution of the nerves, as well as on the nervous centres.[^[49]] The following considerations support this view. 1. Chloroform has the effect of diminishing the sensibility of a part to which it is applied locally, even to the sound cuticle. When the cuticle is removed, the local anæsthesia of the surface is complete; and in frogs, which have a thin permeable skin, and a languid circulation, one limb can be rendered insensible, by the local application of this agent, before the remainder of the animal is much affected. 2. Chloroform when inhaled immediately circulates throughout the body, in all parts of which it can be detected by chemical means. 3. Chloroform and other narcotics suspend the function of the nerves, when locally applied to them. 4. When inhaled, the local effect of chloroform must be greatest when it has had time to exude through the coats of the vessels, into the extra vascular liquor sanguinis, and come into immediate contact with the nervous fibrillæ; and it must take some little time after the chief part of the chloroform has escaped from the blood during its passage through the lungs, before that which is in the lymph external to the vessels can pass back again into them, by endosmosis. The brain, on the other hand, is without lymph and lymphatics. The blood in this organ is all contained within the vessels, in which, moreover, it circulates with more velocity than in the external parts of the body. It can be easily understood, therefore, how the brain may escape from the effects of the vapour whilst the nerves of sensation throughout the body still remain partially under its influence. 5. It is in young subjects, in whom, connected with the more active process of nutrition, the quantity of lymph external to the vessels is greatest, that the general insensibility most frequently remains, whilst the cerebral hemispheres are resuming their functions; whilst in persons of spare habit, approaching the middle or later periods of life, there is little anæsthesia except in the unconscious state.

The co-operation of the brain with the nerves is, of course, necessary to sensation; and it is possible by a large dose of chloroform to produce complete anæsthesia very suddenly, before there is time for the nerves to be acted on locally to any extent; and if the chloroform is not continued, the anæsthesia may subside as quickly as it was induced. The large ganglia of sensation, the optic thalami, seem to require a greater quantity of chloroform to suspend their function than is necessary to suspend that of the cerebral hemispheres, but, by occupying three or four minutes in giving chloroform, one is enabled to add its local action on the nerves to its influence on the brain, and thus to induce anæsthesia with less narcotism of the nervous centres than would otherwise be required.

It must not be supposed that the difference of the action of chloroform on the cerebral hemispheres, and on the optic thalami, will of itself explain the want of uniformity between the loss of consciousness and loss of feeling. If it were a mere difference of degree, it might be so explained; but the absence of all regular relation between these phenomena can only be satisfactorily accounted for when the circumstances connected with the circulation and the liquor sanguinis, that I have endeavoured to explain above, are taken into account.

In the fourth degree of narcotism, the breathing is stertorous, the pupils are dilated, and the muscles completely relaxed. The patient is always perfectly insensible. It is very seldom necessary to carry the effects of chloroform as far as this degree. It is, however, sometimes requisite to do so, in attempting to reduce dislocations of long standing in muscular persons, and whilst the surgeon is dissecting in the neighbourhood of important vessels and nerves, in certain robust subjects and others who seem to have acquired an excess of sensibility by hard drinking, and who can hardly be kept quiet under the knife, except when the breathing is stertorous.

There are some further effects of chloroform with which one becomes acquainted in experiments on the lower animals. If the inhalation is continued after the symptoms just described are produced, the breathing is rendered difficult, feeble, or irregular, and is sometimes performed only by the diaphragm, whilst the intercostal muscles are paralysed. If the dose of chloroform is gradually increased after these effects are produced, the breathing entirely ceases, but the heart continues to pulsate very distinctly, till its action becomes arrested by the absence of respiration, as in asphyxia. This interval, including the embarrassment and cessation of the breathing, I call the fifth degree of narcotism.

Although the respiration may be suspended by an amount of chloroform that has very little direct effect in the motion of the heart, it is quite possible to stop the heart’s action by the immediate effect of this agent. When frogs are exposed to the action of the vapour, they go on absorbing it by the skin, after the respiratory movements have ceased; and in this way the pulsations of the heart are arrested, when a certain amount of chloroform has been absorbed into the blood. And when animals of warm blood are made to breathe air containing as much as eight or ten per cent. of the vapour of chloroform, the blood which is passing through the lungs becomes so charged with it as to stop the action of the heart, when it reaches that organ through the coronary arteries. It is in this way that accidents from chloroform have happened. The power of this agent to arrest the pulsations of the heart can also be shewn, by blowing a stream of the vapour on its surface, when the chest is opened immediately after the breathing has ceased, and whilst it is still beating.

The ultimate and greatest effect that chloroform is capable of producing on the animal body is to destroy the irritability of the muscles, and produce the post-mortem rigidity. Either the whole body or a single limb can be rendered instantly rigid by injecting the arteries with a little chloroform shaken up with water. The rigidity remains for weeks in the dead body, and would probably be permanent if the chloroform were prevented from evaporating. Whilst it lasts, putrefaction is of course prevented.

Effect of Chloroform on the Pulse. I have not mentioned the state of the pulse in the above description of the effects of chloroform, for it affords no criterion of the amount of narcotism, and it was better therefore to reserve it for a separate notice. It is nearly always increased both in force and frequency, more especially at the early part of the inhalation. After the patient has become quite insensible, the pulse indeed generally settles down nearly to the natural standard, and in the middle of the most formidable operations, it is often beating with natural volume and force, not more than sixty or seventy times a minute. The pulse rarely becomes weaker or slower than natural under the influence of chloroform, except from considerable loss of blood, or where the patient is about to be sick. I have twice found the pulse as slow as 44 in the minute at the conclusion of an operation attended with great loss of blood. One of the cases was the removal of a large tumour of the labium pudendi, in a woman, aged forty-five, on the 28th of April, 1849, at King’s College Hospital, by Mr. Fergusson. The pulse was, however, not small or weak, and there was no faintness. In a few minutes, the patient vomited, and the pulse immediately resumed its natural frequency.[^[50]]

There is occasionally a feeble state of pulse with a feeling of faintness as the effects of the chloroform subside, and in two or three cases in which the patient was in a sitting posture, positive syncope occurred, which, however, was promptly removed by the horizontal position. The persons most liable to a feeling of faintness after chloroform, are those who are subject to syncope from slight causes.

Action of Chloroform on the Nervous System. Chloroform, when inhaled, immediately reaches every part of the nervous system through the circulation, and it acts on every part of that system from the first, as a careful observation of the symptoms proves. It does not, however, act equally on all parts of the nervous system, according to the quantity which is absorbed; some parts of that system have their functions entirely, or almost, suspended, whilst others are but little under the influence of the vapour, and it is owing to this fact that the most severe pain may be prevented without danger. M. Flourens made the following remarks respecting the action of sulphuric ether, and they apply equally well to the effects of chloroform, when it is inhaled gradually: “Under the action of ether, the nervous centres lose their powers in regular succession—first, the cerebral lobes lose theirs, viz., the intellect; next, the cerebellum loses its, viz., the power of regulating locomotion; thirdly, the spinal marrow loses the principle of sensitiveness and of motion; the medulla oblongata still retains its functions, and the animal continues to live: with loss of power in the medulla oblongata, life is lost.”[^[51]] I may add, that after the breathing has ceased, from the loss of power of the medulla oblongata, the ganglionic nerves still perform their functions, and the heart and intestines continue to move for a time, often with vigour.

Owing to the unequal effects of a given quantity of chloroform on different parts of the nervous centres, and owing to its acting also on the nerves, a variety of states may be met with during a surgical operation, some of which have often been thought curious, or anomalous. The most usual state of the patient during an operation, when chloroform is successfully administered, is one of perfect quietude, without any sign of consciousness or sensation. The patient under chloroform may, however, moan, or cry, or flinch, or show other symptoms which are usually thought indicative of pain, but without using any articulate language, or remembering anything of the operation afterwards. If his flinching or crying out has neither interfered with the surgeon, nor distressed the friends who may be present, a case of this kind may be considered satisfactory. A third condition of the patient under the influence of chloroform is that in which he talks, or laughs, or sings during the operation, his words having no reference to what is being done. If he is sufficiently quiet for the proceedings of the surgeon, the application of the chloroform must be considered successful, and this condition proves the absence of pain even more completely than that in which there is neither sign nor sound, except the breathing and pulsation of the heart and blood vessels. A fourth condition of the patient is that in which he is conscious, and can look on whilst the surgeon is performing some small operation, or the minor part of a large one, without feeling it, or whilst feeling it in a manner which is not painful. This condition, when it occurs, is the most satisfactory proof of the power of chloroform to prevent pain. It happens but rarely, however, and cannot be induced at will, and it is usually at the concluding part of an operation, during which the patient has been unconscious, that this condition is met with. He wakes whilst there is still a vessel to tie, or a suture to be introduced, and does not feel it, owing, as was stated before, to some of the chloroform being detained in the extra vascular liquor sanguinis, whilst the brain has become almost free from the medicine. When the knife, or the needle, is felt without being painful, it is because the common sensibility, without being entirely abolished, is so much reduced, that what would otherwise cause acute pain only occasions an ordinary sensation.

A fifth state of the patient is met with when an insufficient quantity of chloroform has been administered, or when its effects have been allowed to subside too soon. The patient may call out or complain in articulate words, such as “Oh, you are hurting me,” and yet may assert afterwards that he had no pain, and knew nothing whatever of the operation. His own language at the time must, however, be held to decide that there was some pain, which made so slight an impression on the disordered mind as not to remain in the memory. Pain which is not remembered is of very little consequence, and probably is but slight in degree. It should not be judged of by the expressions of the patient when he is but partially conscious, and using no self-control. Chloroform may, lastly, be administered so badly, that the patient simply falls asleep under the soothing influence of a very gentle dose, as he might sleep from an ordinary dose of opium, without being insensible, and, when the operation is commenced he wakes to full consciousness, and both feels pain and remembers it.

Patients, when insensible, sometimes moan or groan from the effects of the chloroform, and quite independently of the operation. The groaning or moaning comes on sometimes and even leaves off again, before the operation is commenced. When symptoms like those of pain are present during an operation, one may generally know whether they are the consequences of it, by observing whether or not they are connected with each cut of the knife. But even when a flinch or a groan follows each manipulation of the surgeon, it does not necessarily follow, provided the patient does not speak, that he is suffering pain. Some amount of consciousness is essential to the presence of pain, but many of the lower animals execute movements like those caused by pain, after the head is cut off, and when, of course, there can be no consciousness. Although the mind, under ordinary circumstances, is conscious of the attitude, gestures, and cries, which accompany pain, neither the intellect nor the will have any share in their production. On the contrary, they usually take place in spite of the efforts of the will to prevent them, and one may understand that, when consciousness and volition are suspended, the actions usually indicative of pain may, for want of control, be excited by slighter causes, and to a greater degree, than in the waking state.

It is certain that chloroform may prevent pain in two ways, either by rendering the mind unconscious of external impressions, or by removing the sensibility to these impressions, that is, by a true anæsthetic action, but usually, and always when breathed in a full dose, it acts in both ways at once.

The patient sometimes supposes that he remembers all the particulars of the operation, although he did not feel the pain, but on questioning him it is usually found that it is a dream which he remembers, and not the actual facts. It is extremely rare for a patient to assert that he has felt pain from the operation, when he has not felt it, but I have known this to happen once or twice, and a circumstance which was related to me by Mr. Robinson proves the possibility of it. He administered chloroform, or ether, to a lady, with the intention of extracting some teeth, but could not succeed in getting the mouth open, and the lady woke before anything had been done, and asserted that she had felt the operation. She inhaled again, and awoke, and repeated the same statement once or twice before the teeth were actually extracted.

I have heard it stated that patients have felt the pain of the operation, but have been unable to make any sign of feeling it. Such an occurrence may possibly take place when the chloroform is inhaled too slowly, or not in sufficient quantity; but I have not witnessed it, and it evidently cannot happen with a sufficient dose.

CIRCUMSTANCES WHICH INFLUENCE OR MODIFY THE EFFECTS OF CHLOROFORM.

I arrived at the conclusion, after much careful observation, that chloroform might be given with safety and advantage in every case in which the patient requires, and is in a condition to undergo, a surgical operation; and having acted on this conclusion for several years, I have found no reason to change it. It is desirable, however, to pay attention to every circumstance connected with the health and constitution of the patient before exhibiting chloroform, as many of these circumstances influence its effects.

Age. The age of the patient has considerable influence in modifying the effects of chloroform. It acts very favourably on children: they sometimes oppose the inhalation of it as long as they are conscious, but it does not occasion the rigidity and struggling after loss of consciousness, which are sometimes met with in the adult. Anæsthesia is generally induced with a less amount of narcotism of the nervous centres in children than in grown up persons. The effects of chloroform are more quickly produced and also subside more quickly in children than in adults, owing no doubt to the quicker breathing and circulation. It often happens, however, that when the insensibility has been kept up for some time, say twenty minutes or half an hour, in a child, it is followed by a natural sleep of a few hours duration, provided there is no painful wound, or other cause, to prevent the sleep. I have given chloroform in a few cases as early as the ages of eight and ten days, and in a considerable number before the age of two months; and I have at this time, June 30th, 1857, memoranda of the cases of 186 infants under a year old to whom I have administered this agent. There have been no ill effects from it either in these cases, or in those of children more advanced in life; and it is worthy of remark that none of the accidents from chloroform which have been recorded, have occurred to young children.

There is nothing peculiar in the effects of chloroform on people advanced in years, except that its influence subsides rather slowly, on account of the slower breathing and circulation. I have given chloroform to many patients over seventy-five years of age, and to one as old as ninety years.

Strength or Debility. The comparative strength or debility of the patient has considerable influence on the way in which chloroform acts. Usually the more feeble the patient is, whether from illness, or any other cause, the more quietly does he become insensible; whilst if he is strong and robust, there is very likely to be mental excitement in the second degree, and rigidity of the muscles, and probably struggling in the third degree of narcotism. Patients in a state of debility resemble children, not only in coming quietly and easily under the influence of chloroform, but also in the circumstance, that the common sensibility is suspended with less narcotism of the nervous centres than is generally required in robust persons. Children and persons in a state of debility have usually an acute sensibility which causes them to suffer pain from very slight injuries, but this sensibility is more easily suspended by chloroform than the less acute sensibility of robust persons. It is in strong men, accustomed to hard work or athletic sports, that the rigidity and struggling previously alluded to in describing the effects of chloroform, most frequently occur after the loss of consciousness. Some of the patients in whom the struggling and rigidity have been greatest were gentlemen belonging to boating clubs; but I think the patient, in whom these symptoms were most violent, was a celebrated harlequin of one of the London theatres, on whom Mr. Fergusson operated a few years ago.

The persons in whom the rigidity and struggling are well marked are often lean and wiry, and these symptoms rarely occur in fat people. The rigidity and struggling are less marked when the chloroform is given slowly than when quickly given.

Hysteria. Patients who are subject to hysteria sometimes have symptoms of the complaint, such as sobbing, crying, or laughing, as soon as consciousness is suspended, or even impaired, by the chloroform; but these symptoms can always be subdued by proceeding with the inhalation. In a very few instances the hysterical state returns, and becomes troublesome as the effect of the vapour subsides. In two or three cases that I have met with, it continued for three or four hours, but it usually subsides in a much shorter time. The inhalation should not be suspended on account of the hysteria, but should be continued till it is subdued before an operation is performed.

I have rarely seen a decided fit of hysteria from the effects of chloroform, but in the case of a young married lady, to whom I gave this agent to prevent the pain of an operation on the rectum, a somewhat violent paroxysm of hysteria came on directly after the inhalation was commenced. The surgeon would not permit me to continue the chloroform, and expressed his intention of operating without it. After waiting for about half an hour, however, for the hysteria to subside, and finding that it continued the same as at first, the inhalation was resumed. The patient was soon rendered insensible, and lay perfectly still whilst the operation was performed. There was a little hysteria as the effects of the chloroform subsided, but not so severe as before.

I have several times seen hysterical symptoms in the male, either during the administration of chloroform, or whilst the patient was recovering from its effects. But in all these cases, the patients informed me afterwards that they were subject to hysterics when under the influence of mental emotion.

In some persons who are subject to hysteria, the breathing becomes excessively deep and rapid whilst inhaling chloroform. This usually occurs just as the patient is becoming unconscious, but in a few cases even earlier, and the patient is aware of the impulse to breathe in this manner. After this kind of hysterical breathing has lasted a minute, the patient generally rests nearly a minute without breathing at all, after which the respiration generally becomes nearly natural. I give the chloroform very sparingly during this violent breathing, or else withdraw it altogether for a minute or two.

I do not consider that the hysterical diathesis forms any objection to the use of chloroform in operations, as the patients would be generally quite as liable to suffer an attack of hysteria from the pain, if chloroform were not used.

Epilepsy. Chloroform occasionally brings on a fit of epilepsy in persons who are subject to this disease. It was stated in one of the foreign medical journals, in 1848, that this agent was so certain to cause a fit in epileptic persons, that it might be used to detect impostors pretending to be subject to this disease; but if this assertion has been acted on, it must have led to great injustice, for I have many times administered chloroform to the extent of causing complete insensibility in epileptic patients who required to undergo operations, without its inducing the least approach to a fit.

In the few cases in which epileptic convulsions are occasioned by chloroform, they do not appear till the third degree of narcotism is induced, in this respect differing from hysteria, which comes on in the second degree, or even earlier, as was stated above. The course to pursue, when epileptic convulsions appear, is to continue the chloroform steadily and gently, till they subside. I have never seen the chloroform fail to subdue the convulsions in a very few minutes, and I have never seen them recur after the operation, as the effects of the vapour subsided. In medical and obstetric practice, and for slight operations, it is not requisite to carry the effects of chloroform so far as that stage in which an epileptic fit would occur, so that under these circumstances the fact of a patient being subject to epilepsy hardly requires to be taken into account.

Pregnancy. I have repeatedly given chloroform at all periods of pregnancy, both for tooth-drawing and more important operations, and I have not met with any ill effects from it in any of the cases.

The Menstrual Period. It is customary to avoid the menstrual period in fixing the time for a surgical operation, when it can be so arranged. There are, however, often reasons for not waiting over this period, and under such circumstances, I do not know any objection to the inhalation of chloroform. I have administered it frequently during the menstrual period, and have seen no ill effects from it. I have observed that there is a little more tendency to slight hysterical symptoms, during its inhalation at this period, than when the same patients inhale it at other times, which is what we might expect.

Diseases of the Lungs. Affections of the lungs sometimes cause a little difficulty and delay in the administration of chloroform, as the vapour is liable to excite coughing when the mucous membrane of the air-passages is irritable. The inconvenience is, however, confined to the time of inhalation, for the cough is generally relieved afterwards.

I have given chloroform for surgical operations in many cases where phthisis was present, and in several patients who had suffered from hæmoptysis, and have not seen any ill effects from its use in these cases. Chloroform has indeed often been inhaled with advantage to relieve the cough in consumption. The cases of chronic bronchitis in which chloroform is administered for surgical operations are still more numerous. The effects I have observed have been coughing at the time of inhalation, and very often a relief of the cough afterwards. Some of the patients had emphysema of the lungs. It is scarcely necessary to allude, in this place, to acute diseases of the lungs, as surgical operations are not performed during their continuance, but from the fact of chloroform being inhaled occasionally in the treatment of these affections, it is evident that they would cause no obstacle to its employment.

Disease of the Heart. There is a very general impression that the use of chloroform is unsafe when disease of the heart exists, more particularly, fatty degeneration of that organ. This belief has been encouraged by the circumstance that this affection has been present in a few of both the real and alleged deaths from chloroform; and also by the fact that, in the accidents that have been really due to chloroform, the heart has been the organ on which it has exerted its fatal influence. When we come to investigate these cases, however, we shall find reason to conclude that the heart has probably been diseased in quite as great a proportion of the patients who have taken chloroform without ill effects, as in those who have succumbed under its influence. As regards my own practice, indeed, the only case in which death could in any degree be attributed to the chloroform, was one in which there was extreme fatty degeneration of the heart; but, on the other hand, I have given chloroform in numerous cases without ill effects where the symptoms of this, as well as other affections of the heart, were present in a very marked degree. Indeed, I have never declined to give chloroform to a patient requiring a surgical operation, whatever might be his condition, as I early arrived at the conclusion that this agent, when carefully administered, causes less disturbance of the heart and circulation than does severe pain. Whenever I have had an opportunity of seeing an operation performed without chloroform, I have carefully observed the pulse, and although none of these operations have been of a very severe nature, I have found the circulation to be much more disturbed than it would have been by chloroform carefully administered. The pulse in most of these cases has been excessively frequent during the operation, and in some instances it has intermitted to an unusual extent.

In one instance, I had an opportunity of witnessing a similar operation on the same patient, first without chloroform, and afterwards under the influence of this agent. On January the 6th, 1855, Mr. Fergusson performed lithotrity, in King’s College Hospital, on a man, aged fifty-one. He generally directs chloroform to be administered in lithotrity, but in this instance he omitted to do so, as he thought that the bladder was not very irritable, and that the patient would not suffer much. I began to feel the pulse just when the patient saw the lithotrite about to be introduced. It was 120 in the minute. As soon as the instrument was introduced, the pulse increased to 144, and immediately afterwards it became uneven, irregular, and intermitting. I could not count more than three or four beats at a time; and, occasionally, when the pain seemed greatest, and the man was straining and holding his breath, the pulse was altogether absent for four or five seconds. In order to ascertain whether the absence of pulse at the wrist might not depend on the pressure of the muscles of the arms, caused by grasping the table, I applied my ear to the chest, and found that there was no sound whatever to be heard during the intervals when the pulse was imperceptible. It was evident that the patient held his breath till the right cavities of the heart became so distended as to stop the action of that organ till the respiration returned. The man did not complain or cry out during the operation. A week afterwards the lithotrity was repeated, but on this occasion I administered chloroform. The pulse was about 120 in the minute when the patient began to inhale the chloroform, but it became slower as he was made unconscious, and it was regular and natural during the operation. It was only towards the end of the operation, when the effect of the chloroform was allowed to diminish, and when the man began to strain a little, though not yet conscious, that the pulse intermitted slightly, passing over a single beat occasionally. There were none of the long intermissions of the pulse observed on the former occasion.

It is very evident that if the above mentioned patient had been the subject of any affection of the heart which weakened or embarrassed its action, he would have run a much greater risk from the pain of the first operation, than from the inhalation of chloroform in the second one.

In a few of the patients having the arcus senilis of the cornea, a weak, intermitting, or irregular pulse, and other signs of fatty degeneration of the heart, there have been a feeling of faintness and a tendency to syncope, as the effects of the chloroform were subsiding, especially when the operation had been performed in the sitting posture; but these symptoms have soon subsided, in all the cases I have met with, on placing the patient horizontally, with or without the help of a little ammonia to the nostrils.

Cerebral Disease. Affections of the head offer no obstacle to the administration of chloroform. I have given it to several patients who had suffered previously from an attack of apoplexy. Some of them still retained the paralysis resulting from their attack, but the chloroform has not been attended or followed by ill effects in any of these cases. The following case, in which alarming head symptoms had existed a few hours before the inhalation of chloroform, cannot fail to be interesting.

The 31st of October, 1854, was appointed by Mr. Fergusson to perform lithotrity on a gentleman, seventy-eight years of age, who had a phosphatic calculus in his bladder. He was a patient of Mr. Propert, and Mr. Fergusson had removed a similar calculus by lithotrity, and I had given him chloroform at each of the operations, and it was arranged that he should have chloroform on the present occasion. Mr. Propert informed Mr. Fergusson and me, on our arrival, that his patient had had an attack the night before resembling apoplexy; he had been insensible, the breathing had been stertorous, the pupils dilated, and the face very red and congested. Mr. Propert had caused him to be cupped to fourteen ounces, and had given him twenty grains of calomel in the course of the night, and in the morning he was as well as usual, and remained so at the time of our visit. We considered the case with Mr. Propert, and as there were reasons for not postponing the operation, it was determined that he should inhale the chloroform rather than be subjected to the pain. The vapour acted very favourably; he recovered his consciousness a few minutes after the operation, and expressed himself as feeling quite well.

Mr. Fergusson crushed another calculus in this patient in March 1855, when I again administered chloroform, and in 1856 I understood that he was free from the complaint.

Insanity. Chloroform acts on insane patients just as it does on others, that is to say, they are made insensible by it, and, when its effects completely subside, it leaves them in the same state of mind as before. Insane people are, however, often so suspicious that they cannot be persuaded to inhale chloroform, and it can only be given to them by force. When once under its influence, however, I have seen teeth extracted, and other operations performed, which it would have been impossible to accomplish in the same individuals without resorting to inhalation. The use of chloroform in the treatment of mania will be alluded to in another part of this work.

Hard Drinkers. It was at one time alleged that hard drinkers of spirituous liquors were not susceptible of the influence of ether or chloroform, and for a long time there remained an impression that these persons were difficult to render insensible. I have always found that hard drinkers were rendered unconscious, and even comatose, by the same amount of ether or chloroform as other persons; but they sometimes have a morbid excess of sensibility in the nerves of common sensation, and do not lie still under the surgeon’s knife except when the nervous centres are deeply narcotised, and the breathing almost stertorous. On this account, they sometimes inhale much more chloroform during a protracted operation than other persons.

AMOUNT OF VAPOUR OF CHLOROFORM ABSORBED TO CAUSE THE VARIOUS DEGREES OF NARCOTISM.

Before proceeding to describe the mode of administering chloroform, it is desirable to treat of the quantity of it which produces its different effects. Without alluding to the facts and experiments which prove that all narcotics produce their effects by being absorbed into the circulating fluid, and so reaching the nervous system on which they act, it is only necessary to mention the following circumstances to show that this is the case as regards chloroform. In some experiments in which I assisted Dr. Sibson, we found that the vapour of chloroform produced its effects after both the pneumogastric nerves had been divided, exactly the same as before. Chloroform can be detected by means of chemical tests exhaling in the breath of those who have just previously inhaled it. It can also be detected in the urine after inhalation, and very readily in all the tissues of animals that have been killed by it, for several days after death.

The quantity of chloroform in the blood in the different degrees of narcotism might be estimated approximatively from the amount used in inhalation, but I devised some experiments in 1848 for ascertaining the quantity with accuracy.[^[52]] The experiments were based on the following circumstances.

When air containing vapour is brought in contact with a liquid, as water or serum of blood, absorption of the vapour takes place, and continues till an equilibrium is established; when the quantity of vapour in both the liquid and air, bears the same relative proportion to the quantity which would be required to saturate them at the temperature and pressure to which they are exposed.

This is only what would be expected to occur; but I verified it by numerous experiments in graduated jars over mercury. The intervention of a thin animal membrane may alter the rapidity of absorption, but cannot cause more vapour to be transmitted than the liquid with which it is imbued can dissolve. The temperature of the air in the cells of the lungs and that of the blood circulating over their parietes is the same; and, therefore, when the vapour is too dilute to cause death, and is breathed till no increased effect is produced, the following formula will express the quantity of any substance absorbed:—As the proportion of vapour in the air breathed is to the proportion that the air, or the space occupied by it, would contain if saturated at the temperature of the blood, so is the proportion of vapour absorbed into the blood to the proportion the blood would dissolve.

The manner in which the experiments were performed, was to place a small animal in a glass jar, so large that it formed a capacious apartment for it, and held much more air than it could require in the course of the experiment. The jar was covered with a closely fitting lid, and a carefully weighed portion of chloroform was allowed to diffuse itself through the air of the jar. The experiments were continued till the chloroform produced no further effect. I shall pass over a number of tentative experiments, and adduce only a few of those which were made after I had ascertained the quantities requisite to produce the desired effect. The results obtained in these experiments were entirely due to the degree of dilution of the vapour; for the quantity of chloroform employed was, in every instance, more than would have killed the animal in a much shorter time than the experiment lasted, if it had been conducted in a smaller jar. It is assumed that the proportions of vapour and air remain unaltered during the experiment; for the quantity absorbed must be limited to what the animal can breathe in the time, which is so small a part of the whole that it may be disregarded.

Experiment 1. A guineapig and a white mouse were placed in a jar holding 3,000 cubic inches, and fifteen grains of chloroform were introduced by a tube in the lid of the jar, which was closed immediately by a screw. The chloroform fell on some blotting paper suspended in the jar, and in a minute or two was converted into vapour and diffused through the air in the jar. The animals were allowed to remain half an hour, and were unaffected by the chloroform, except that they appeared to be a little less brisk than usual, during the first two or three minutes after their removal.

Experiment 2. A guineapig was placed in the same jar, and twenty-two and a half grains of chloroform were introduced in the same manner as before, being three-quarters of a grain to each hundred cubic inches of air. In two or three minutes the chloroform was converted into vapour and diffused through the air in the jar. Six minutes afterwards the guineapig began to stagger, and soon afterwards was unable to keep on its legs. It was kept for half an hour in the jar, but did not become further affected. It was occasionally quiet, but always tried to walk when disturbed by moving the jar. When taken out, it flinched on being pricked, and it tried to walk, although unable to support itself on its legs. It recovered from the effects of the chloroform in three or four minutes.

Experiment 3. Another guineapig was placed in the same jar, and thirty grains of chloroform were introduced. In three or four minutes the chloroform had evaporated and diffused itself through the air in the jar. In two minutes afterwards the guineapig lay down, but stirred when the jar was moved. It was allowed to remain in the jar for half an hour, being asleep except when disturbed. When taken out it awoke and endeavoured to walk, but was unable to support itself at first. It flinched on being pricked. Recovered in three or four minutes.

Experiment 4. A cat was placed in the same jar, and the same quantity of chloroform was introduced. In three minutes it had evaporated, and, when ten minutes had elapsed, the cat began to stagger. Soon afterwards it was unable to support itself on its legs; and, when a quarter of an hour had elapsed, it seemed asleep, but raised its head when the jar was inclined. It remained apparently sleeping till the end of an hour, when it was taken out. It was unable to stand, but was sensible to the slightest pinch. It recovered gradually in the course of twenty minutes.

Experiment 5. Sixteen grains of chloroform were put into a jar holding 1,600 cubic inches, being one grain to each 100 cubic inches of air, as in the two last experiments. When it was converted into vapour, a white mouse was introduced, by moving the lid a little to one side for a moment. After running about for a minute and a half, it began to stagger and to lose power, but it continued to run with little intermission till three minutes had expired. After this it lay still, except when the jar was inclined, when it always endeavoured to maintain its balance and to walk. It also moved its limbs now and then, when not disturbed. It was removed at the end of ten minutes, when it tried to walk, but was unable. It did not flinch when its tail was pinched, but flinched, half a minute after its removal, on one of its toes being pinched. It recovered in two or three minutes.

Experiment 6. A guineapig was placed in the jar holding 3,000 cubic inches, and 37·5 grains of chloroform were introduced in the same manner as in the former experiments, being a grain and a quarter to each 100 cubic inches of air. The chloroform took three or four minutes to evaporate and diffuse itself in the jar; and by the end of this time the guineapig, which had been excited and running about, began to stagger, and in two minutes longer it was unable to walk, but endeavoured to keep its balance when the jar was inclined. At the end of a quarter of an hour it was lying still, but moved its limbs when it was rolled over by inclining the jar; but it made no voluntary effort. It was taken out when thirty-three minutes had elapsed. It moved its limbs as it was removed, though apparently not in a voluntary manner. Its limbs were not relaxed. It was quite insensible to pricking. It recovered in about ten minutes. The temperature in the axilla before it was put into the jar was 100° Fah., and immediately after its removal 96°.

Experiment 7. A guineapig was placed in the same jar, and forty-five grains of chloroform were introduced, being a grain and a half to each 100 cubic inches of air. In four minutes after the chloroform had evaporated, the guineapig was unable to walk. In half a minute more it seemed asleep, but there was a tremulous motion of the hind legs, which continued till ten minutes had elapsed. Afterwards it lay still, but winked now and then spontaneously. When rolled over by moving the jar, it made no voluntary effort. It was taken out twenty minutes after the chloroform had evaporated. It winked spontaneously, and also when the eyes were touched. It did not flinch when the ear was pricked, but flinched when the paw was pricked. The temperature in the axilla before the experiment was 100°, and immediately afterwards it was 96°. The guineapig recovered from the effects of the chloroform in ten minutes.

Experiment 8. A guineapig was put into the same jar, and 52·5 grains of chloroform were introduced, being a grain and three-quarters to each 100 cubic inches of air. The chloroform evaporated in the course of four minutes, at the end of which time the guineapig was altered in its manner, as if partially inebriated. In two minutes more it was becoming drowsy. A little while afterwards it was lying down. Six minutes after the evaporation of the chloroform was complete, the guineapig made no effort when turned over by inclining the jar, but only moved its feet, as it were automatically. At the end of nine minutes, it was lying quietly and breathing naturally. When fifteen minutes had elapsed it was in the same condition, and was removed from the jar. It cried and flinched on the foot being pricked. The temperature in the axilla was 97°. In five minutes after its removal it was fast recovering, and in ten minutes was quite recovered.

Experiment 9. A guineapig was placed in the jar used in the last three experiments, and sixty grains of chloroform were introduced in the same manner, being two grains to each 100 cubic inches of air. In four minutes it was all converted into vapour, and the guineapig was beginning to be affected by it. In two minutes more it was unable to stand or walk. In five minutes from the time when the evaporation was complete, the guineapig showed no sign of sensibility when turned over by inclining the jar; the breathing was natural. At the end of ten minutes it was lying still, breathing gently forty times in the minute. At the end of fifteen minutes it was in the same condition. From seventeen to twenty minutes, it stretched out one of its hind legs several times, and was doing so when taken out, at the end of twenty minutes. It showed no sign of sensibility when pricked. The temperature in the axilla was 96°. It began to recover gradually in a minute or two, and recovered completely in from ten to fifteen minutes.

Experiment 10. A cat was placed in the same jar, and the same quantity of chloroform was introduced in the same manner. It became quite insensible in a few minutes after the chloroform was introduced; and it was allowed to remain for twenty-five minutes, when it was taken out. It was perfectly insensible to pricking, and its muscles were quite relaxed; it was breathing gently, and the pulsations of the heart were between sixty and seventy in the minute. It was immediately made the subject of another experiment of drowning whilst insensible, which need not be related in this place.

Experiment 11. Four grains of chloroform were put into a glass jar holding 200 cubic inches, and when it had evaporated and was diffused through the air in the jar, a white mouse was introduced, by momentarily removing the cover a little to one side. A minute after its introduction the mouse was lying, but it moved its legs for a quarter of a minute longer. When four minutes had elapsed, the breathing became slow, and it was taken out. It was totally insensible for the first three minutes after its removal, and recovered during the two following minutes.

Experiment 12. Thirty-two grains of chloroform were diffused through the air of a jar holding 1,600 cubic inches, being two grains to each 100 cubic inches, as in the last three experiments. A white mouse was introduced by moving the cover a little to one side for a moment. In one minute it was insensible, and did not make any effort on being rolled about by inclining the jar, but it moved its paws for half a minute longer. It remained insensible, breathing 160 times in the minute, till it was taken out at the end of five minutes. It was quite insensible to pinching. It began to walk in a minute or two. Its temperature before the experiment was 98°, and immediately afterwards was 92°. The temperature of the room was 68°.

Experiment 13. A guineapig was put into a jar holding 3,000 cubic inches, and 67·5 grains of chloroform were introduced on blotting paper suspended within the jar, being 2¼ grains to each 100 cubic inches. In four minutes, the chloroform had all evaporated, and the guineapig was becoming affected. In two minutes more, it was quite insensible. Eight minutes after the chloroform had evaporated, it was lying still, breathing forty times in the minute. During the next three or four minutes, it moved one or other of its legs occasionally. At the end of seventeen minutes, it was lying still, and the breathing was twenty-six in the minute. It was taken out at the end of twenty minutes quite insensible; in three or four minutes it began to try to walk, and in ten minutes, was quite recovered.

Experiment 14. Two white mice, one being full grown, and the other about three-quarters grown, were placed in the jar holding 1,600 cubic inches, and forty grains of chloroform were introduced on blotting paper, being two grains and a half to each hundred cubic inches. In two minutes, the chloroform had evaporated, and the mice were much excited. In another minute, they were unsteady in walking; and in a minute more, the old mouse was lying insensible, and breathing deeply and laboriously. In four minutes more, i. e., six minutes after the chloroform had evaporated, the young mouse was insensible also, but was moving one of its hind legs. In other four minutes, the young mouse was breathing by slow gasps, whilst the old one continued to breathe deeply as before. Three minutes later, i. e., thirteen minutes after the chloroform had evaporated, the old mouse had begun to gasp, and the young one was gasping only at intervals. They were removed, and recovered completely in ten minutes. The young one recovered most quickly. Their temperature, on being removed, was about 90°.

Experiment 15. A cat was put into the jar holding 3,000 cubic inches, and 82·5 grains of chloroform were introduced, being two grains and three-quarters to each hundred cubic inches. In five minutes, it had evaporated, and the cat began to stagger in its walk. In two minutes more, it was unable to stand. Five minutes after the chloroform had evaporated, the cat was breathing deeply, seventy-five times in the minute. At eight minutes, it was breathing less deeply, one hundred and seventeen times in the minute. Ten minutes after the chloroform had evaporated, the cat was quite insensible, and breathing one hundred and twenty-six times in the minute. It was now taken out. The temperature in the axilla was 98°. In half an hour after its removal from the jar, it had recovered its consciousness, but was still drowsy.

It was now put into the jar again, and the same quantity of chloroform was introduced in the same manner as before. In five minutes, it had evaporated, and the cat was again insensible. In other five minutes, it was breathing rather deeply, forty-eight times in the minute. Twelve minutes after the chloroform had evaporated, the cat was breathing in the same manner, but sixty-eight times in the minute. The breathing afterwards became shallow and feeble, and half an hour after the chloroform had evaporated, it was eighty-eight in the minute. In five minutes more, the breathing ceased. The cat was taken out of the jar, and the stethoscope was applied to the chest. The heart could not be heard to beat at first, but in a short time, the cat gave a gasp, and the heart’s action returned, and the breathing became reestablished.

Experiment 16. Forty-eight grains of chloroform were put into a jar holding 1,600 cubic inches, being three grains to each hundred cubic inches, and when it was converted into vapour and diffused through the air in the jar, a white mouse was introduced. It ran about for a minute and a half, and then it was unable to move any longer. In nine minutes and a half, the breathing was getting very slow, and the mouse was immediately removed. Before it could be got out, it appeared to have entirely ceased to breathe, but it immediately began to gasp at intervals. In a minute, the breathing improved, and soon became natural. Three minutes after its removal, the mouse began to walk in a ring, and in seven minutes, it had quite recovered.

Experiment 17. A guineapig was placed in a jar holding 1,600 cubic inches, and fifty-four grains of chloroform were introduced on blotting paper, in the manner previously explained; being three grains and three-eighths to each hundred cubic inches of air. In four minutes, the chloroform had evaporated, and become diffused through the air in the jar, and the guineapig was drowsy. In three minutes more, it was lying apparently insensible, and breathing feebly, thirty times in the minute. After this, it kicked occasionally for a few minutes. When six minutes had elapsed from the time when the chloroform had evaporated, the breathing was very feeble, and apparently performed only by the diaphragm. From fifteen to eighteen minutes, I could hardly see whether the animal was breathing or not, and it was taken out of the glass at eighteen minutes, when the breathing appeared to have ceased. The stethoscope was applied to the chest, and the sounds of the heart could scarcely be heard at first, but the breathing returned in a few seconds, and the action of the heart improved. The guineapig gradually recovered, but it was not able to walk for twenty-five minutes.

Experiment 18. Sixty grains of chloroform were introduced into the jar employed in the last experiment, being three grains and three-quarters to each hundred cubic inches of air contained in the jar. When it had evaporated, and was diffused through the air, a white mouse was introduced, whilst the lid of the jar was moved a little to one side for a moment. It ran about at first, but suddenly ceased to run, and became insensible, at the end of three-quarters of a minute. It lay breathing deeply and rapidly till two minutes had elapsed, when the respiration became slow, and it ceased at two minutes and three-quarters after the mouse was introduced. It was removed at this time, and it gasped a few seconds afterwards; this gasp was soon followed by another; the gaspings became more frequent, and in a short time, the natural breathing was resumed. In five minutes, the mouse was able to walk.

The third, fourth, and fifth of the above experiments show that one grain of chloroform to each hundred cubic inches of air suffices to induce the second degree of narcotism, or that state in which consciousness and voluntary motion are disturbed, but not entirely abolished. Now one grain of chloroform produces 0·767 of a cubic inch of vapour at 60°, when its specific gravity is 4·2; and, when the vapour is inhaled, it expands somewhat, as it is warmed to the temperature of the lungs; but it expands only to the same extent as the air with which it is mixed, and therefore the proportions remain unaltered. But air, when saturated with vapour of chloroform at 100°, contains 43·3 cubic inches in 100; and

As 0·767 : 43·3 :: 0·0177 : 1.

So that if the point of complete saturation be considered as unity, 0·0177 or 1–56th, will express the degree of saturation of the air from which the vapour is immediately absorbed into the blood; and, consequently, also the degree of saturation of the blood itself.

I find that serum of blood at 100°, and at the ordinary pressure of the atmosphere, will dissolve about its own volume of vapour of chloroform; and since chloroform of specific gravity 1·483 is 288 times as heavy as its own vapour, 0·0177 ÷ 288 gives 0·0000614, or one part in 16,285, as the average proportion of chloroform by measure in the blood, in the second degree of narcotism.

It is evident, from the experiments numbered 9 to 12 inclusive, that two grains of chloroform to each hundred cubic inches of the inspired air cause a state of very complete insensibility, corresponding with what I have designated the fourth degree of narcotism; and by the method of calculation employed above we get 0·0354, or 1–28th, as representing the degree of saturation of the blood, and 0·0001228 the proportion by measure in the blood.

In experiments 6, 7, and 8, in which quantities of chloroform were employed intermediate between one and two grains to each hundred cubic inches of air, a moderate amount of insensibility was induced, corresponding very much with the state of patients during operations under chloroform.

The experiments from 13 to 18 show that quantities of chloroform, exceeding two grains to 100 cubic inches of air, have a tendency to embarrass and arrest the function of respiration, if the inhalation is continued. I have not yet been able to determine satisfactorily the exact proportion of chloroform which requires to be absorbed to arrest the respiration of animals of warm blood. I believe there is a definite proportion which has this effect, but there are two reasons why it is not so easy to ascertain it, as to ascertain the proportion which causes the minor degrees of narcotism. In the first place, the breathing often becomes very feeble before it ceases, so that the animal inhales and absorbs but very little chloroform, and remains on the brink of dying for some time. In the next place, the temperature of the body falls in a deep state of narcotism, especially in small animals; and, as the temperature falls, the amount of chloroform which the blood can dissolve from any given mixture of air and vapour increases.

Judging from the experiments numbered 14 to 18, three grains of chloroform to each hundred cubic inches of air must be very nearly the quantity which has the power of arresting the breathing when the temperature of the body is 100°; and as three grains of chloroform produce 2·3 cubic inches of vapour, and air at 100° is capable of taking up 43·3 per cent. of its volume, it follows that the blood must contain between 1–18th and 1–19th as much chloroform as it is capable of dissolving, at the time when the respiration is arrested. In the 14th experiment, the breathing of the two mice was on the point of being stopped by two and a half grains of chloroform in each hundred cubic inches of air, but during the thirteen minutes which the mice breathed the vapour, their temperature fell to about 90°. Air, when saturated with the vapour of chloroform at this temperature, contains 35 per cent., and two grains and a half of chloroform yield 1·917 cubic inches of vapour; so by a calculation similar to that made at page 68, the mice at the time when the breathing was about to cease must have absorbed 1–18th part as much chloroform as their circulating fluids were capable of dissolving.

The reader will have observed that, in the experiments related above, the mice became much more quickly affected than the guineapigs and cats. The reason of this is their quicker respiration and circulation, and much more diminutive size. Little birds, such as linnets and sparrows, are also very quickly affected by chloroform. Frogs are more slowly affected, owing to their languid respiration, unless the vapour to which they are exposed is very strong.

They can, however, owing to their low temperature, be rendered insensible by proportions of vapour too small to affect animals of warm blood; and as they have no proper temperature of their own, the amount of vapour (in proportion to the air in which they are placed) that will affect them, depends entirely on the temperature of that air.

The following experiment was several times performed on frogs with the same result, the temperature of the room being about 55°, as it was in winter.

Experiment 19. 4·6 grains of chloroform were diffused through the air of a jar of the capacity of 920 cubic inches, and a frog was introduced. In a few minutes, it became affected, and at the end of ten minutes, was quite motionless and flaccid; but the respiration was still going on. Being now taken out, it was found to be insensible to pricking: it recovered in a quarter of an hour.

In a repetition of this experiment, in which the frog continued a few minutes longer in the vapour, the respiration ceased, and the recovery was more tardy. On one occasion, the frog was left in the jar for an hour, but when taken out, and turned on its back, the pulsations of the heart could be seen. In an hour after its removal, it was found to be completely recovered.

The first of the experiments related above (page 60), showed that an atmosphere containing half a grain of chloroform to each hundred cubic inches, produced scarcely any appreciable effect on animals of warm blood; but the following calculation explains why this quantity acts so energetically on the frog, and proves that this creature is affected by chloroform according to the same law as animals of warm blood. The vapour is absorbed into the blood and lymph of the frog at the temperature of the external air, whose point of relative saturation therefore remains unaltered, both in the lungs and in contact with the skin of the animal; and as half a grain of chloroform produces 0·383 cubic inches of vapour, and air at 55° contains, when saturated, 10 per cent. of vapour; 0·0383, or 1–26th, expresses the degree of saturation of the air, and also of the blood of the frog. And this is a very little more than the quantity (0·0354 or 1–28th) which was calculated above to be the greatest amount which could be absorbed with safety into the blood of the mammalia. It must be observed, however, that the pulmonary respiration of the frog was arrested by this proportion of 1–26th as much chloroform as the blood would dissolve, whilst we calculated that it required about as much as 1–18th to arrest the breathing of animals of warm blood. It must be remembered, however, that the pulmonary respiration of frogs is a process of swallowing air, which only goes on when the creature is comparatively active. In the torpid state, the respiration takes place only by the skin, and the frog never breathes with the aid of the same muscles and nerves as mammalia and birds.

By warming a frog, together with the air in which it is placed, it is, in accordance with the law explained above, rendered comparatively proof against an amount of chloroform which would otherwise render it insensible.

Experiment 20. A frog, which had been a few days previously subjected to the experiment just narrated, was put into the same jar, which was placed near the fire, till a thermometer inside marked 75° Fah.; 4·6 grains of chloroform were then introduced, and diffused through the air in the jar. The jar was kept for twenty minutes, with the thermometer indicating the same temperature within one degree. For the first seventeen minutes, the frog was unaffected; and only was dull and sluggish, but not insensible, when taken out. Air at 75°, when saturated with vapour of chloroform, contains 22 per cent., and therefore the 0·383 per cent. of vapour, which at 55° was capable of saturating the fluids of the frog to the extent of 1–26th of what they would dissolve, was, at 75°, capable of saturating them only to the extent of 1–57th.

At one of Dr. Wilson’s Lumleian Lectures, at the College of Physicians, on March 29th, 1848, I had the honour of performing some experiments, and making some remarks, on chloroform, and I combined together two experiments on frogs and small birds, in a way which shows how entirely the effects of a narcotic vapour depend on the quantity of air with which it is mixed, and on other physical conditions.

Experiment 21. I introduced a chaffinch, in a very small cage, into a glass jar holding nearly 1,000 cubic inches, and put a frog into the same jar, covered it with a plate of glass, and dropped five grains of chloroform on a piece of blotting paper suspended within. In less than ten minutes, the frog was insensible, but the bird was not affected.

Experiment 22. I then placed another frog and another small bird in a jar containing but 200 cubic inches, with exactly the same quantity of chloroform. In about a minute and a half, they were both taken out,—the bird totally insensible, but the frog not appreciably affected, as from its less active respiration it had not had time to absorb much of the vapour.

The blood in the human adult is estimated by M. Valentin to average about thirty pounds. M. Valentin’s experiments were so conducted that this quantity must include the extra vascular liquor sanguinis, as well as the blood actually contained within the vessels. On this account, his estimate is all the better fitted for calculating the amount of chloroform absorbed, since this medicine, when inhaled gradually, passes by exosmosis through the coats of the bloodvessels into the fluid in which the tissues are immediately bathed. The above quantity of blood would contain 26 pounds 5 ounces of serum, which, allowing for its specific gravity, would measure 410 fluid ounces. This being reduced to minims, and multiplied by 0·0000614, the proportion of chloroform in the blood required to produce narcotism to the second degree (see page 68), gives 12 minims as the whole quantity in the blood. More than this is used in practice, because a considerable portion is not absorbed, being thrown out again when it has proceeded no further than the trachea, the mouth and nostrils, or even the face-piece. But I find that if I put twelve minims into a bladder containing a little air, and breathe it over and over again, in the manner of taking nitrous oxide, it suffices to remove consciousness, producing the second degree of its effects.

To induce the third degree of narcotism, or the condition in which surgical operations are usually commenced, would require that about 18 minims should be absorbed by an adult of average size and health, according to the above method of calculation; and to induce the deep state of insensibility, which I have termed the fourth degree of narcotism, would require 24 minims; whilst to arrest the function of respiration would require that about 36 minims should be absorbed.

PREPARATIONS FOR INHALING CHLOROFORM.

The only direction which it is usually requisite to give beforehand, to the patient who is to inhale chloroform, is to avoid taking a meal previous to the inhalation; for chloroform is very apt to cause vomiting, if inhaled whilst there is a quantity of food in the stomach. The sickness is not attended with any danger, but it constitutes an unpleasantness and inconvenience which it is desirable to avoid. The best time of all for an operation under chloroform is before breakfast, but the customs and arrangements of this country do not often admit of that time being chosen, and it is unadvisable to make the patient fast beyond his usual hour. It answers very well to perform an operation about the time when the patient would be ready for another meal, or, if the time of operation fall two or three hours after the usual time of eating, to request the patient to make only a slender repast at that time, so as just to prevent the feeling of hunger. It is impossible to prevent vomiting in some cases with the best precautions, for the stomach occasionally will not digest when the patient is expecting a surgical operation, and the breakfast may be rejected in an unaltered state hours after it has been taken. In other cases the patient does not vomit, even when he inhales chloroform shortly after a full meal.

The most convenient position in which the patient can be placed whilst taking chloroform is lying on the back, or side, as he is then duly supported in the state of insensibility, and can be more easily restrained if he struggle whilst becoming insensible. The semi-recumbent posture on a sofa does very well, and there is no objection to the sitting posture, when that is most convenient to the operator. In that case, however, the patient should be placed in a large easy chair with a high back, so that the head as well as the trunk may be supported without any effort, otherwise he would have a tendency to slide or fall when insensible. It has been said that it is unsafe to give chloroform in the sitting posture, on the supposition that it would in some cases so weaken the power of the heart, as to render it unable to send the blood to the brain. Observation has proved, however, that chloroform usually increases the force of the circulation; and although the horizontal position is certainly the best for the patient under an operation in all circumstances, I consider that the sitting posture is by no means a source of danger, when chloroform is given, if the ordinary precaution be used, which would be used without chloroform—that of placing the patient horizontally if symptoms of faintness come on. I have preserved notes of nine hundred and forty-nine cases in which I have given chloroform to patients in the sitting posture, and no ill effects have arisen in any of these cases.

The person who is about to inhale chloroform is occasionally in a state of alarm, either about that agent itself or the operation which calls for its use. It is desirable to allay the patient’s fears, if possible, before he begins to inhale, as he will then be able to breathe in a more regular and tranquil manner. In a few cases, however, the apprehensions of the patient cannot be removed, and they subside only as he becomes unconscious from the inhalation. It has been said that chloroform ought not to be administered if the patient is very much afraid, on the supposition that fear makes the chloroform dangerous. This is, however, a mistake; the danger, if any, lies in the fear itself. Two cases will be related hereafter in which the patients died suddenly from fear, whilst they were beginning to inhale chloroform, and before they were affected by it; but the probability is that, if they had lived till the chloroform took effect, they would have been as safe as other patients who inhaled it. If chloroform were denied to the patients who are much afraid, the nervous and feeble, who most require it, would often be deprived of its benefits. Moreover, the patients would either be prevented altogether from having the advantage of surgery, or they would be subjected to the still greater fear of the pain, as well as the pain itself; for whatever undefined and unreasoning fears a patient may have when the moment comes for inhaling chloroform, he has only chosen to inhale it on account of a still greater fear of pain.

Fear and chloroform are each of them capable of causing death, just as infancy and old age both predispose to bronchitis, but it seems impossible that fear should combine with the effects of chloroform to cause danger, when that agent is administered with the usual precautions. Fear is an affection of the mind, and can no longer exist when the patient is unconscious; but the action of that amount of chloroform which is consistent even with disordered consciousness is stimulating, and increases the force and frequency of the pulse, in the same way as alcohol. I believe that no one would assert that a person would die the sooner of fright for having taken a few glasses of wine, or a small amount of distilled spirits, whatever might be the state of his health. When chloroform has been absorbed in sufficient quantity to cause unconsciousness, fear subsides, and with the fear its effects on the circulation. It is a subject of almost daily observation with me that the pulse, which is extremely rapid from some ill defined apprehension, when certain patients begin to inhale chloroform, settles down to its natural frequency after they become unconscious.

The practice I have always followed has been to try to calm the patient, by the assurance that there was nothing to apprehend from the chloroform, and that it would be sure to prevent all pain; but where it has been impossible to remove the fears of the patient in this way, I have always proceeded to remove them by causing a state of unconsciousness. It would of course be wrong to choose a moment for beginning the inhalation, when fear was producing a very marked depression of the circulation. On feeling the pulse of a gentleman, about twenty-one years of age, in March 1855, who had just seated himself in the chair to take chloroform, previous to having some teeth extracted, by Mr. Thos. A. Rogers, I found it to be small, weak, and intermitting, and it became more feeble as I was feeling it. I told the patient that he would feel no pain, and that he had nothing whatever to apprehend. His pulse immediately improved. He inhaled the chloroform, had his teeth extracted, woke up, and recovered without any feeling of depression. Now if the inhalation had been commenced in this case, without inquiry or explanation, the syncope which seemed approaching would probably have taken place, and it would have had the appearance of being caused by the chloroform, although not so in reality.

MODE OF ADMINISTERING CHLOROFORM.

The experiments previously related show that air containing rather less than two grains of chloroform, in one hundred cubic inches, is capable of causing a state of insensibility, sufficiently deep for surgical operations; but in a creature the size of the human being, an inconvenient length of time would be occupied in causing insensibility with vapour so much diluted. About four cubic inches of vapour, or rather more than five grains of chloroform to each hundred cubic inches of air, is the proportion which I have found most suitable in practice for causing insensibility to surgical operations. In medical and obstetric cases, it should be inhaled in a more diluted form.

Dr. Simpson recommended chloroform to be administered on a handkerchief—the method in which sulphuric ether was administered by Dr. Morton, in the first case in which he exhibited that medicine. The objection to giving chloroform on a handkerchief, especially in surgical operations, where it is necessary to cause insensibility, is that the proportions of vapour and of air which the patient breathes cannot be properly regulated. Indeed, the advocates of this plan proceed on the supposition that there is no occasion to regulate these proportions, and that it is only requisite that the patient should have sufficient air for the purposes of respiration, and sufficient chloroform to induce insensibility, and all will be right.[^[53]] The truth is, however, that if there be too much vapour of chloroform in the air the patient breathes, it may cause sudden death, even without previous insensibility, and whilst the blood in the lungs is of a florid colour. Chloroform may indeed be inhaled freely from a handkerchief without danger, when it is diluted with one or two parts by measure of spirits of wine, but the chloroform evaporates in largest quantity at first, and less afterwards, until a portion of the spirit is left behind by itself. The process, however, of inhaling chloroform from a handkerchief is always uncertain and irregular, and is apt to confirm the belief in peculiarities of constitution, idiosyncrasies and predispositions, which have no existence in the patient.[^[54]]

The most exact way in which it is practicable to exhibit chloroform to a patient about to undergo an operation, is to introduce a measured quantity into a bag or balloon of known size, then to fill it up by means of the bellows, and allow the patient to inhale from it; the expired air being prevented from returning into the balloon, by one of the valves of the face-piece to which it is attached. I tried this plan in a few cases, in 1849, with so much chloroform in the balloon as produced four per cent. of vapour in proportion to the air. The effects were extremely uniform, the patients becoming insensible in three or four minutes, according to the greater or less freedom of respiration; and the vapour was easily breathed, owing to its being so equally mixed with the air. I did not try, however, to introduce this plan into general use, as the balloon would sometimes have been in the way of the surgeon, and filling it with the bellows would have occasioned a little trouble. It seemed necessary to sacrifice a little of absolute perfection to convenience, and I therefore continued the plan which I had already followed.

The great point to be observed in causing insensibility by any narcotic vapour, is to present to the patient such a mixture of vapour and air as will produce its effects gradually, and enable the medical man to stop at the right moment. Insensibility is not caused so much by giving a dose as by performing a process. Nature supplies but one mixture of diluted oxygen, from which each creature draws as much as it requires, and so, in causing narcotism by inhalation, if a proper mixture of air and vapour is supplied, each patient will gradually inhale the requisite quantity of the latter to cause insensibility, according to his size and strength. It is indeed desirable to vary the proportions of vapour and air, but rather according to the purpose one has in view, whether medicinal, obstetric, or surgical, than on account of the age or strength of the patient; for the respiratory process bears such a relation to the latter circumstances, as to cause each person to draw his own proper dose from a similar atmosphere in a suitable time.