BRONCHIAL ASTHMA.

BY W. H. GEDDINGS, M.D.

SYNONYMS.—Asthma convulsivum (Willis); Spasmus bronchialis (Romberg); Asthma nervosum; Krampf der bronchien.

DEFINITION.—A violent form of paroxysmal dyspnoea, not dependent upon structural lesion; characterized by wheezing respiration, with great prolongation of the expiration, and by the absence of all symptoms of the disease during the intervals between the attacks.

HISTORY.—Derived from the Greek [Greek: asthmatnô] to gasp for breath, the term asthma was employed by the older writers to designate a variety of affections of which embarrassed respiration was the most prominent symptom, thus including a great number of diseases which a more extended knowledge of pathology has since distributed among other nosological groups. By the earlier authors simple embarrassment of breathing was designated as dyspnoea; if attended with wheezing it was called asthma; while those forms in which the difficulty in respiration was so great as to prevent the patient from lying down were appropriately styled orthopnoea (Celsus). Ignorant to a great extent of pathological anatomy and unprovided with the improved methods of physical diagnosis which we now possess, they described as asthma not only the dyspnoea due to cardiac and pulmonary diseases, but also that occasioned by affections of the pleura and greater vessels. Covering such an extensive range of territory, it was found necessary to subdivide the disease into a number of varieties, each author classifying them according to his conception of the cause, seat, and nature of the trouble. Some of these—e.g. a. dyspepticum—still find a place in medical literature, but the vast majority of them, having ceased to be of any practical significance, have been discarded, and are now only interesting as examples of the crude and fanciful notions which prevailed in an age during which science rather retrograded than advanced.1 Of the writers of this period, Willis in the seventeenth century is especially worthy of notice as being the first to describe the nervous character of asthma. Without discarding the accepted forms of the disease, he mentions another variety, characterized by spasmodic action of the muscles of the chest, to which he gave the name asthma convulsivum.

1 "Van Helmont, discarding the ancient doctrine of the four humors, attributed asthma to an error of the Archeus, which he conceived to be enthroned in the stomach and to constitute the source of all diseased as well as of all healthy phenomena. This principle, he supposed, sent forth from the stomach a peculiar fluid, which, when it became diseased, gives rise to a morbid state of the parts to which it was conveyed. He moreover imagined that this fluid sometimes mixed itself with the male semen, and thus formed a compound which, as one of its constituents is the means provided by nature for the propagation of the species, possesses the power of generating a disease of hereditary character. Thus, when this compound was conveyed to the articulations, he affirmed it produced gout, and when it took its direction to the lungs it then occasioned asthma" (Baltimore Med. and Surg. Journ. and Review, Baltimore, 1833, p. 300).

The improvement in physical diagnosis resulting from the brilliant discoveries of Auenbrugger and Laennec greatly curtailed the domain of asthma. With the aid of auscultation and percussion it was discovered that most of the cases hitherto regarded as asthma were only symptoms of some organic disease. Many distinguished authorities, particularly of the French school, went so far as to declare that there existed no such disease as asthma, and that in every case the dyspnoea and other phenomena described under that name were merely symptoms of some organic affection.

Although very generally received at first, it was not long before this too-sweeping reform encountered opposition from various quarters. Cases were observed with marked asthmatic symptoms in which, after death, the most careful examination failed to reveal the slightest trace of textural lesion. The discovery by Reisseisen of muscular fibres even in the minutest bronchi, and the demonstration of their electric contractility by Longet and Williams, afforded a ready explanation of these cases, and led to the opinion—which has since been generally received—that asthma in the modern acceptation of the term is simply a neurosis. The more recent theories in regard to the nature of asthma will be more fully discussed in the portion of our article devoted to the pathology of the disease.

SYMPTOMS AND COURSE.—The following description of an attack of asthma by Trousseau, who was himself an asthmatic, is perhaps the best that has ever been written: "An individual in perfect health goes to bed feeling as well as usual, and drops off quietly to sleep, but after an hour or two he is suddenly awakened by a most distressing attack of dyspnoea. He feels as though his chest were constricted or compressed, and has a sense of considerable distress; he breathes with difficulty, and his breathing is accompanied by a laryngo-tracheal whistling sound. The dyspnoea and sense of anxiety increasing, he sits up, rests on his hands, with his arms put back, while his face is turgid, occasionally livid, red, or bluish, his eyes prominent, and his skin bedewed with perspiration. He is soon obliged to jump from his bed, and if the room in which he sleeps be not very lofty he hastens to throw his window open in search of air. Fresh air, playing freely about, relieves him. Yet the fit lasts one or two hours or more, and then terminates. The face recovers its natural complexion and ceases to be turgid. The urine, which was at first clear and was passed rather frequently, now diminishes in quantity, becomes redder, and sometimes deposits a sediment. At last the patient lies down and falls to sleep."

The next day the patient may feel well enough to pursue his accustomed avocation, and may remain free from all symptoms of the disease until another attack comes on; but more frequently he is confined to the house, if not to bed, the slightest exertion being sufficient to cause dyspnoea; and during the following night there is a repetition of the paroxysm.

If unchecked by treatment, the disease may continue for days, weeks, and in some instances even for months, the paroxysms often increasing in severity until, as in other nervous affections, it ultimately wears itself out.

There is no regularity in the occurrence of the attacks. In some cases they recur every few days, while in others there may be an interval of weeks or months between the seizures. Even in the same case, although the individual paroxysms of the attack may come on at the same hour, there is, except in rare instances, no regularity in the recurrence of the attack itself; and when it does recur at a certain time it is almost always due to some cause which, as in hay asthma, exerts its influence only at that particular period.

In the great majority of cases asthma comes on without any warning whatsoever, but occasionally it is preceded by certain sensations which to the experienced asthmatic are a sure indication that an attack is impending. With some it is only a feeling of ill-defined discomfort; others complain of various disorders of the digestive system—a sense of dryness of the mouth and pharynx, uncomfortable distension of the epigastrium with eructation of gases from the stomach, and more or less obstinate constipation. A troublesome itching of the skin often precedes the attack. Some experience a feeling of constriction around the throat; a profuse secretion of clear urine is a symptom of this stage. Frequent gaping, frontal and occipital headache, are mentioned; but far more constant than all of these are certain symptoms indicative of a mild grade of acute catarrh of the respiratory organs—coryza, with swelling of the Schneiderian membrane and discharge from the nostrils, sneezing, redness of the conjunctivæ with increased lachrymation, and later, as the irritation extends downward, more or less cough.

The attack almost always comes on after midnight, and, as a rule, between the hours of two and six o'clock in the morning. Salter states that nineteen out of twenty cases occur between two and four A.M. There are, however, occasional exceptions to this rule; sometimes the patient is attacked soon after retiring, and Trousseau cites the case of his mother, who always had her attacks between eight and ten in the forenoon, and also that of a tailor, whose paroxysms invariably came on at three o'clock in the afternoon. Indeed, there is no hour of the twenty-four during which the seizure may not take place. Various attempts have been made to explain why it is that the paroxysms of asthma almost invariably occur during the latter half of the night. Many attribute it to a stasis of blood in the lungs caused by the recumbent posture of the patient, while others claim that it is due to a dulling of reflex impression, the patient during sleep failing to perceive the necessity of breathing. Germain Sée, who discredits both theories, inquires why, if the above explanations are correct, does the attack not come on soon after retiring, as is the case with the dyspnoea of cardiac diseases.

The paroxysm of asthma develops very rapidly, but not so suddenly as is claimed by many authors, several minutes to half an hour or more elapsing before it attains its full height.2

2 Germain Sée in Nouveau Dictionnaire de Médecine et de Chirurgie, tome iii. p. 617, Paris, 1865.

The patient, experiencing an urgent desire for breath, instinctively places himself in the position most favorable for the ready admission of air into the lungs. If in bed he sits up, and, resting on his hands or grasping his knees with them, he so fixes the body that the muscles of respiration may work to the greatest advantage. The shoulders are drawn up and the head thrown back. The expression of the face is one of great anxiety—pale at first, then red, and as the attack increases in severity assumes a dusky, bluish tint; the mouth is partially opened, the nostrils are dilated; the eyes, the conjunctivæ of which are much injected, are prominent, with a wild, staring look; and the forehead is moist with perspiration. Others in their desperate struggle for breath spring from the bed, throw open the window, and, regardless of everything save what they believe to be impending suffocation, recklessly gasp in the cold night air. Sometimes the sufferer prefers to kneel before a table or some other article of furniture, supporting his head with his hands. Whatever posture he assumes, he is actuated by the one impulse of placing himself in the position that will enable him to use to the greatest advantage the muscles of respiration and their auxiliaries. The sterno-cleido-mastoid muscles are contracted to the utmost, and, projecting like hard cords, with the aid of other muscles draw the chest upward. The patient instinctively avoids every unnecessary exertion as having a tendency to aggravate his dyspnoea; he speaks but little, and when questioned usually replies with a motion of the head.

In ordinary respiration the inspiratory movement is twice as long as the expirium, the latter, except in forced expiration, being a purely passive act. In asthma this rule is reversed, the expiratory movement being four or five times as long as the inspirium, and is often so slow that it fills the whole of the pause which usually intervenes between the completion of one respiration and the beginning of another. It is sometimes so slow "that it seems as though the lung would never empty itself." In the desperate struggle for breath the respiratory muscles are exerted to the utmost in futile endeavors to expand the chest; with each inspiration there is an elongation of the thorax, but no lateral movement. The chest moves up and down, but there is no expansion; "the muscles tug at the ribs, but the ribs refuse to rise" (Salter), the walls of the chest remaining immovable.

Notwithstanding the all but tetanic contraction of the diaphragm, there is during each inspiration a sinking in of the epigastrium, and in severe cases also of the spaces above and below the clavicles. During expiration the abdominal muscles, especially the recti, are hard and tense, the pressure thus exerted being sometimes sufficient to expel the contents of the lower bowel and bladder.3 The transversus is also tightly contracted, and a cross furrow above the umbilicus indicates that the contraction of its upper half is opposed to the contents of the abdomen forced down by the distended lung (Biermer). Although the dyspnoea is great, there is no increase in the frequency of the respirations so long as the patient remains quiet, but, on the contrary, they are often less frequent than in health. This slowing of the respiration is also observed in the dyspnoea from laryngeal stenosis in croup, etc.; but in these cases we do not have the prolonged expiration which is so characteristic of asthma (Biermer). At every breath which the patient takes there is a peculiar wheezing sound which may be heard distinctly all over the room; it is usually heard only during expiration, but some authors (Biermer) claim that it is also audible during inspiration.

3 Bamberger's case, as quoted by Riegel, Ziemssen's Pathologie u. Therapie, Leipzig, 1875, Band iv. 2, S. 282.

On auscultating the chest it will be found that the ordinary vesicular murmur is either entirely absent, or if heard it is only over very limited areas. In the place of it we have an endless and ever-changing variety of dry sounds, such as whistling, cooing, mewing, snoring, etc., technically styled sibilant or sonorous ronchi. They are usually equally diffused over both lungs, but are sometimes confined to one. The sibilant râles afford an index of the degree of spasm, being in mild cases equally audible during both inspiration and expiration, while in severe attacks they are louder during expiration (Biermer). That the vesicular murmur cannot be heard is due not only to its being masked by the louder ronchi, but also to the absence of the condition necessary for its production, the spasmodic constriction of the bronchial tubes or their plugging with tough, viscid mucus preventing the entrance of sufficient air to produce the sound. Sometimes a hitherto occluded tube becomes pervious, and we have vesicular respiration where a moment before only dry sibilant râles were heard. Usually at the close of the attack, when cough sets in, there are occasional moist râles. These become more frequent as the expectoration becomes more abundant. Frequently, however, the paroxysm terminates much more abruptly, the spasm relaxes, and the air rushing through the tubes gives rise to puerile respiration.

During the paroxysm there is, even in the early stages of asthma, more or less distension of the lungs, measurement of the chest showing that its circumference is four to eight centimeters greater than before the attack (Beau). This transitory emphysema, which must not be confounded with that due to structural changes observed in old cases, disappears with the attack, and the lung returns to its normal condition. This distension causes the exaggerated resonance obtained by percussion which is one of the most constant symptoms. At the base of the lung, especially posteriorly and laterally, there is a peculiar modification of the percussion sound to which Biermer has applied the name Schachtelton, from its resemblance to the note produced by striking an empty pasteboard box. Besides this exaggerated resonance, it will be found that the line of dulness on the right side, which marks the upper border of the liver, is fully two inches lower during the paroxysm than before, and that the area of cardiac dulness is somewhat diminished by the overlapping of the distended lung-tissue (Riegel). Another peculiarity elicited by percussion, and to which Bamberger was the first to direct attention, is that in some rare cases instead of moving vertically the line of hepatic dulness remains unchanged during both acts of respiration.

Toward the close of the attack the congested mucous membrane of the bronchi begins to secrete, and there is more or less cough. The matter expectorated consists at first of little balls of tough, semi-transparent mucus not much larger than a pea. It is exceedingly tenacious, and is raised with great difficulty. Examined under the microscope, the sputum is found to consist "of a great number of corpuscles, some of which are polyhedral in form with rounded angles; they are pale, homogeneous, and slightly granular. At first sight they resemble pus-corpuscles, but they are much larger, less circular in form, and have no nucleus. In addition to these corpuscles there are others which are oval, elongated, fusiform, and sometimes linear in shape, but all of them appear to be of the same nature and possess the same refracting power as the corpuscles first mentioned. They are all of them agglomerated in a sort of viscous matter."4 The expectoration often contains blood, and in some rare instances profuse hemorrhages have been known to occur. Sometimes the matter has particles of soot and coal-dust intermingled with it, the so-called carbonaceous sputum (Sée). In addition to the cells above described, the sputa contains small yellowish-green masses or threads in which are imbedded the peculiar octahedral crystals which Leyden has ingeniously connected with the etiology of asthma, and to which we shall again have occasion to refer.5 Ungar has recently also discovered crystals of oxalate of lime in the sputa.

4 Germain Sée, Nouveau Dictionnaire de Médecine et de Chirurgie, pp. 612, 613; also, Salter, Asthma, its Pathology and Treatment, Am. ed., p. 944.

5 Riegel, in Ziemssen's Handbuch d. Pathologie u. Therapie, vol. iv. 2, pp. 268, 285.

Laryngoscopic examination reveals more or less congestion of the air-passages. "In ordinary respiration the glottis is widely open during inspiration, and at each expiration the arytenoid cartilages approach each other so as to narrow the glottis; but in the labored respiration of asthma the glottis is fixed in the condition of expiration; that is, the glottis is narrowed, and the air enters and is expired through the same narrow space."6

6 Steavenson, Spasmodic Asthma, p. 23.

The embarrassment of respiration and the pressure of the air in the distended alveolæ by impeding the capillary circulation of the lungs prevent the left auricle from receiving its full supply of blood; hence the pulse is small and weak during the paroxysm, but regains its natural volume as soon as its immediate effects are over. The action of the heart, like every other phenomenon of asthma, is subject to constant variation. At one moment it beats tumultuously, while at the next its action may be so feeble as to cause temporary syncope (Sée). The venous blood, unable to overcome the obstacles to its passage, is forced back into the vessels, causing distension of the cervical veins and the jugular pulse sometimes observed in severe attacks. The bluish hue of the face in bad cases is due to cyanosis resulting from insufficient aëration of the blood. The paroxysm is unattended with fever, the temperature, if altered at all, being rather below than above the normal. Coldness of the face and hands is quite a common symptom in protracted cases.

In addition to the nervous sensations described among the premonitory symptoms, patients have been known to suffer from disturbances of a more serious nature during the paroxysm. In some instances there is complete loss of consciousness, and Riegel7 states that such cases have been known to have tetanic convulsions of the trunk and extremities.

7 Loc. cit. p. 285.

The course of an attack of asthma is in most cases quite typical, the paroxysms recurring nightly for an indefinite period, and usually increasing in severity until, as in epilepsy and other nervous diseases, it finally exhausts itself. On awaking from the sleep which usually succeeds the final paroxysm the patient, unless the attack has been very mild and of short duration, feels weak and exhausted, but there is no tendency to the recurrence of the dyspnoea; on the contrary, he may expose himself with perfect impunity to the causes which at other times would be certain to produce an attack. The chest feels stiff and sore, the cough and expectoration diminish, and in a few days disappear, and if the disease has produced no organic lesion the patient returns to his usual state of health.

DURATION.—The duration of asthma, except in young persons and in those rare cases in which the cause can be discovered and removed, is very indefinite, the disease lasting for years, if not for life. As the patient grows older the attacks become less severe, but are more frequent. Sometimes a case which has recurred for years and defied the most energetic treatment will all at once recover of itself.

SEQUELÆ.—Although bronchial asthma is essentially a neurosis, and therefore purely functional in its character, it is rare for it to continue for any great length of time without causing some organic affection of the lungs or heart.

The most common sequel of asthma is emphysema. The bronchial tubes being more or less completely closed, either by contraction of their muscular fibres or by plugs of thick, viscid mucus, the air pent up in the parts beyond the obstruction is subjected to the negative pressure produced by the exaggerated inspiratory act, becomes rarefied, and, in obedience to the diminished resistance induced by the partial vacuum in the thorax, causes distension of the air-cells. This condition continues until, the tubes having again become pervious, the natural elasticity of the lung-tissue, aided by the expiratory muscles, forces out the air and permits them to return to their natural size. This is the transitory emphysema to which we have already alluded. Germain Sée8 regards it as analogous to the paralytic emphysema which occurs the moment the pneumogastric is divided. With repeated attacks the air-cells lose their elasticity and remain permanently dilated. Owing to the constant distension, the walls of the alveolæ become more and more attenuated, until, finally giving way, two or more of them coalesce, forming one large cell. The symptoms of this condition are the same as those of ordinary vesicular emphysema.

8 Op. cit., p. 637.

Owing to partial occlusion of the afferent bronchi and the altered conditions of pressure mentioned, the blood accumulates in the capillaries during the paroxysm, the lung-cells do not receive their adequate supply of air, and oxygenation is imperfect. In the early stages of the disease this congestion is only temporary, and disappears with the removal of the obstruction, but in those cases in which the attacks are severe and frequent the vessels lose their contractility and remain permanently congested.

The state of chronic congestion just mentioned is occasionally attended with serous exudation into the interalveolar tissue, which by pressing upon the adjacent air-cells causes their obliteration. This oedema, with the remains of the compressed air-cells and the viscid mucus stagnating in the finer tubes, forms the little islets of carnified tissue known as lobular pneumonia.

The most frequent change observed in the bronchial tubes in old cases of asthma is hypertrophy of their muscular fibres, causing thickening of their walls and diminished calibre. In other cases they are dilated, but this condition is due more to the concomitant bronchial catarrh than to the asthma.

Obstructed in its course through the lungs, the venous blood accumulates in the pulmonary artery, and, pressing back upon the right ventricle, excites it to increased action, which in the course of time leads to hypertrophy of its muscular fibres and dilatation of its cavity.

In the early stages of asthma, the face is usually pale during the intervals between the paroxysms, but when the latter become more frequent the impeded circulation causes stasis in the peripheral vessels. The imperfectly-oxygenated blood gives the face a dusky hue, and in severe cases it may become bluish or even violet-colored. The eyes are prominent, owing to the enlargement of the orbital veins (Sée), and the conjunctivæ congested and watery.9

9 For a description of symptoms of the above-mentioned secondary affections the reader is referred to the articles on [EMPHYSEMA] and [HEART DISEASE].

ETIOLOGY.—Predisposing Causes.—Every one is not liable to asthma, and the fact that out of a large number exposed to its exciting causes only a few are attacked justifies the assumption that there is an inherent tendency to the disease. That this tendency is hereditary in its nature is conceded by every prominent writer on asthma except Lebert, who believes this to be only occasionally the case. Thus, of 35 cases collected by Salter, heredity could be traced in 14, of whom 7 inherited the disease from the father, and the remainder from grandparents and other relations. Ramadge gives an instance in which the disease appeared in four generations: an asthmatic father had four children, three of whom inherited the disease; one of the daughters married, and of her two children one became asthmatic; the other escaped, but the disease reappeared in one of her children.10

10 Germain Sée, op. cit., p. 668.

The hereditary tendency may skip one generation, as is the case with Steavenson,11 who inherited asthma from his grandfather, his father's generation having been entirely free from the disease. In other cases it may alternate with some other neurosis or with gout or rheumatism; for instance, the children of an asthmatic father may be epileptic or gouty and the grandchildren asthmatic, or the asthmatic tendency may develop in one child of an asthmatic family and the gouty diathesis in another. It is by no means necessary for the hereditary transmission of the disease that the father should be asthmatic when the child is conceived, as there are many cases recorded in which asthma developed in children whose fathers had completely recovered before they contracted marriage and never had any subsequent return of the disease.

11 W. E. Steavenson, Spasmodic Asthma, London, 1882, p. 8.

All authorities agree that asthma is much more frequent among males than females. Of Théry's cases, 60 were females and 80 males. The more recent statistics of Salter show that the males exceed the females in the proportion of two to one. This undue frequency of a purely nervous disease among males appears at first to be at variance with the generally-received opinion that such affections pertain rather to the female sex; but on investigating the ages at which the attacks first come on it will be found that between the fifteenth and thirtieth years—that is, during the period when sexual function is most active—the proportion is reversed, females being attacked much oftener than males.

Asthma occurs more frequently in childhood than at any subsequent period—a fact which may be explained by the great susceptibility of young children to catarrhal affections of the air-passages and to the frequent occurrence at that age of measles and whooping cough (Salter). Of 225 cases collected by Salter, 71 occurred before the tenth year, and of these, 10 began during the first year, the youngest of them being only fourteen days old at the time of the attack. From ten to twenty it occurs less frequently than at any other period of life, but from that age to the fortieth year there is a steady increase in the number of cases. During the next decade, from forty to fifty, the disease diminishes in frequency, and from that period on the number of cases continues to grow smaller and smaller with advancing years, comparatively few commencing after the fiftieth year.

The following tabular statement, compiled by Salter, shows the comparative frequency of asthma during the various periods of life:

From1 to 10years,71cases.
"10 to 20"30"
"20 to 30"39"
"30 to 40"44"
"40 to 50"24"
"50 to 60"12"
"60 to 70"4"
"70 to 80"1"

These figures demonstrate the fallacy of the popular idea that old people are especially liable to asthma. Its prevalence during the later periods of life is due to the fact that while, on the one hand, the affection rarely causes death, on the other it is scarcely ever curable except during childhood, and thus the cases contracted at different ages accumulate and form a large aggregate as life advances.

Those cases occurring in childhood and late in life are likely to be associated with more or less bronchial catarrh, while those which come on when the body has attained its fullest development are almost invariably purely nervous in character.

The period of life at which asthma commences is an important element in the prognosis of the disease, the cases occurring in early childhood being likely to end in recovery, while those coming on later in life are exceedingly protracted in their course and liable to lead to organic diseases of the heart or lungs.

Asthma does not appear to be influenced by the seasons, some authors claiming that it is most frequent in summer, while others maintain that the greatest number of cases occur in winter.

Exciting Causes.—Bronchial asthma being a neurosis of the pneumogastric nerve, its exciting causes may be divided into those which act upon the nerve directly, and those which are reflected from more remote parts or organs.

In the first class the irritant may act upon the nerve at its origin in the medulla oblongata or upon some part of its continuity. Various poisons, organic or inorganic, when introduced into the system may so change the character and composition of the blood as to interfere with the nutrition of the respiratory centre, and thus cause more or less embarrassment of respiration; but the attacks of dyspnoea due to these causes are more continuous than those of ordinary asthma, and are wanting in many of the symptoms which we have described as characteristic of that disease. These forms of dyspnoea are usually the result either of some constitutional disease or of some poison introduced into the system, both of which act by diminishing the proportion of red corpuscles in the blood. Of this we have examples in the dyspnoea sometimes observed in syphilis and malarial fever and in lead and mercurial poisoning—the so-called a. saturninum and a. mercuriale. It is true that there have been instances in which the paroxysms of asthma have come on at regular intervals and have yielded to quinine, but it is not regarded as proved that such cases were due to malarial poisoning (Sée).

Enlarged bronchial glands pressing upon the pneumogastric nerve may cause asthma, and this explains why it is so frequent in children after attacks of measles and whooping cough (Williams and Biermer). Others have remarked that asthma is often coincident with hypertrophied tonsils (Schaeffer). In the great majority of cases the exciting cause does not act directly upon the pneumogastric nerve, but upon the skin or some other remote organ, whence it is transmitted to the nervous centre and reflected back through the nerves of respiration to the bronchi.

Biermer believes that the irritant in many cases, instead of being directly transmitted to the medulla oblongata, causes a fluxion to the exposed mucous membrane. He thinks that the absence of catarrhal symptoms is more apparent than real, the evidences of congestion being unappreciable during the early stages of the disease. According to Riegel,12 the action of the irritant may be explained in one of three different ways—viz. 1st, both the spasm and the fluxion may be the common result of the irritant; 2d, the catarrh may cause the spasm; or, 3d, the spasm may secondarily produce catarrh.

12 Op. cit., p. 256.

Although cold may not be so frequent a cause of asthma as was formerly supposed, low temperature undoubtedly acts as an irritant upon the terminal branches of the respiratory nerves, especially the pneumogastric, and in the manner just described may produce spasmodic contraction of the bronchi. The effect of cold is of course much more deleterious when it is associated with sudden changes and diminished barometric pressure, high winds from the east and north being particularly prejudicial. Aside from its meteorological characteristics, the locality itself exercises a potent influence in the production of asthma; and here, again, we have an example of the capricious character of the disease. A patient who for years has suffered with asthma may change his residence and find immediate relief, but of the special factors which engender the disease in one place and cure it in another we know as yet but little. It is, however, a generally acknowledged fact that removal from the country to a crowded city will often diminish the severity and frequency of the attacks, and English writers mention numbers of cases of asthma which have been permanently cured by a prolonged residence in the foggy atmosphere of London. A very slight change is often sufficient to afford relief, and sometimes removal to another part of the same city is all that is necessary. The town of Aiken in South Carolina is divided by a ravine into two sections: the elevation, soil, and exposure are alike in almost every respect, but persons have been known to suffer severely with asthma on one side and to enjoy perfect exemption from it on the other. A gentleman who resides at Bath in the same neighborhood is perfectly free from asthma at his home, but invariably has an attack as soon as the train begins to cross the Savannah River at Augusta, which is only a few miles distant. More remarkable still is the case mentioned by a French writer of a young man who was unable to sleep in the front rooms of a house without having a paroxysm, but who did not experience the slightest inconvenience when he occupied the back rooms.

Although removal to the city frequently affords relief, there are exceptions to the rule, and many cases are recorded where a change of residence to the country has effected a cure. Ozone, of which but little is as yet known, is supposed by some to be a cause of asthma, and it is not unlikely that the relief afforded by removal to a large city may be partly due to the relatively small proportion of this agent in the atmosphere of crowded localities.

Dust of various kinds, the pollen of plants, certain vapors, gases, smoke, and the emanations from many species of animals, have all been known to excite attacks of asthma. Some persons are so sensitive that the simple act of brushing their clothes is sufficient to bring on a paroxysm. Others are unable to inhale the perfume of roses, lilies, heliotropes, and many other flowers without suffering with an attack. The dust of hay will often cause paroxysms even in those who are not hay-fever subjects. Since Cullen first published the case of an apothecary's wife who had asthma whenever ipecac was powdered in her husband's shop numerous cases of a similar nature have been recorded. Ramadge relates the case of an employé in the East India Company who was compelled to relinquish a lucrative appointment because the smell of tea always provoked a paroxysm of asthma. Many persons are unable to come into close proximity with horses, rabbits, cats, and other animals without suffering, and Austin Flint of New York experienced great inconvenience when absent from home from sleeping upon feather pillows. In his case the asthmatic attack was not brought on by all pillows, but what it was that made one kind more active than another he was unable to determine.

In persons predisposed to bronchial asthma the eating of any indigestible substance may of itself be sufficient to cause an attack, and even an ordinarily full meal, if partaken of late in the day, may have the same effect. Dyspepsia in its various forms and the presence of irritating substances in the intestinal canal are such frequent causes of asthma that they have led to the establishment of several special varieties of the disease—e.g. a. dyspepticum, a. verminosum.

Asthma is frequently due to uterine and ovarian disorders, the so-called a. uterinum.

Voltolini of Breslau has described cases which were evidently due to the presence of naso-pharyngeal polypi, the attacks disappearing with their removal and reappearing with their renewed growth. These statements have been confirmed by subsequent cases observed by Haenisch. Attention has lately been directed to a number of cases in which the asthmatic paroxysm was found to be associated with catarrh of the naso-pharyngeal and laryngo-tracheal mucous membrane. In such cases it is thought that the irritation caused by the pressure of the swollen mucous membrane upon the adjacent nerves is conveyed through them to the pneumogastric, and thus provokes the bronchial spasm. Daly, Roe, Harrison Allen, Hack, and others have traced the paroxysms of hay asthma to an hypertrophied condition of the mucous membrane over the turbinate bones and septum of the nose, which renders it peculiarly susceptible to the action of the irritants which cause that troublesome affection, and have succeeded in curing many cases by simply removing the diseased tissue.

Mental emotion, if sufficiently powerful, may sometimes prevent the occurrence of the asthmatic paroxysm; thus, Steavenson, referring to his own case, states that although subject to frequent attacks he never had one on going up for an examination; and the writer is acquainted with a patient whose attack of hay asthma could frequently be checked by an exciting game of cards.

Asthma, like other neuroses, is much more frequent among the educated and refined than among the coarser and more ignorant classes of society, and those leading luxurious lives are more liable to the disease than those of simple and frugal habits. Of the various professions, those which involve much exertion of the voice furnish the largest contingent; hence it is common among public speakers, clergymen, and lawyers.

In former days the retrocession of cutaneous eruptions was supposed to play an important rôle in the production of asthma, but of late years this theory of causation has found but few advocates among intelligent physicians, the only author of any prominence who still adheres to it being Waldenburg, who has proposed to designate such cases as a. herpeticum.

PATHOLOGY.—We have elsewhere alluded to the various theories with which the older writers endeavored to explain the phenomena of asthma, and need not here refer to them again.

The first step toward a truly scientific theory of the pathology of asthma was the discovery by Reisseisen of the smooth muscular fibres of the bronchial tubes. These fibres are found not only in the large and medium-sized bronchi, but even in those of the smallest calibre, Kölliker having demonstrated them in bronchioles 0.18 millimeter in diameter. It was ascertained by Williams that by irritating the lung he could cause contraction of these fibres, and Longet subsequently proved that the same effect could be produced by galvanizing the pneumogastric nerve. Guided by these important discoveries, most modern pathologists have arrived at the conclusion that bronchial asthma is a spasmodic contraction of the middle and finer bronchi, dependent upon some derangement in the function of the pneumogastric nerve. This, the so-called spasmodic theory, is not entirely new, Willis, as we have before stated, having described as early as 1682 a variety of asthma which he believed to be the result of a "spasmodic action of the muscles and nerves of respiration," and to which he applied the term "asthma convulsivum." Although revived from time to time, it was not until some two hundred years later, and after Romberg had definitely settled the question of the essential character of the disease, that the spasmodic nature of asthma received general recognition. Bergson adopted it in his prize essay in 1840, and ten years later it found a warm supporter in the person of Hyde Salter, whose valuable contributions have added so much to our knowledge of bronchial asthma. The theory that asthma is due to spasm of the bronchial muscles met with but little opposition until 1854, when Wintrich, after a series of experiments, arrived at conclusions directly opposed to those of Williams and Longet in regard to the contractility of the muscular fibres of the bronchi, and refused to accept the spasm theory on the ground that it afforded no rational explanation of the phenomena of asthma. He believed that the various symptoms of that disease were due to tonic spasm either of the diaphragm alone or of the diaphragm and the other muscles of respiration. These experiments of Wintrich were so carefully conducted, and his standing as a specialist in respiratory diseases so high, that his theory found many supporters, and might perhaps have been generally accepted had it not been for the distinguished French physiologist, Paul Bert, who in 1870, with improved methods of scientific research, succeeded in demonstrating that Williams and Longet were after all correct in their statements as to the contractility of the bronchial muscles.

One of the most zealous advocates of the spasm theory of asthma, and at the same time its most learned expositor, is Biermer,13 whose classical lecture on that disease, which appeared a short time after the publication of Bert's experiments, is perhaps the most satisfactory work ever published on the subject. He defines bronchial asthma as a "neurosis depending upon tonic spasm of the bronchial muscles and caused by faulty innervation of the pneumogastric nerve." He claims that this theory is confirmed by clinical experience—that the suddenness with which the attack comes and disappears, and the long and forced expiration with the sibilant râles and other evidences of stenosis which accompany it, admit of no other explanation. In support of this view he calls attention to the rapidity with which the paroxysm yields to chloral, all of its symptoms disappearing within from five to ten minutes after the administration of a moderate dose of that agent. Wintrich and his supporters, besides denying the contractility of the bronchial muscles, object to the spasm theory that the distension of the thorax and descent of the diaphragm, both constant symptoms, are incompatible with spasmodic closure of the bronchial tubes, and that constriction from such cause by impeding the entrance of air into the alveolæ would be more likely to cause diminution in the size of the thorax than its enlargement, and that the diaphragm, instead of descending, would be drawn upward. Biermer acknowledges that this to a certain extent is true, and concedes that constriction of the tubes would interfere with both acts of respiration, but claims that it does not do so to the same extent in the two movements. The spasmodic constriction acts as a sphincter which is readily overcome during inspiration, but prevents the escape of air during expiration, the latter movement being slower and less complete than the former. Were the expiratory pressure exerted upon the contents of the alveolæ alone, it would readily overcome the spasmodic constriction of the bronchi, but it also compresses at the same time the bronchioles. "When the bronchi are spasmodically contracted, they are subjected during expiration to the general pressure of that movement plus the pressure of the spastic contraction of the bronchial muscles. The walls of the bronchioles being soft and compressible, the expiratory pressure, instead of overcoming the obstruction and opening them, would tend to close them all the more tightly." He calls attention to an analogous condition which obtains in capillary bronchitis, when, owing to swelling of the mucous membrane and to the accumulation of secretion in the tubes, the alveolæ are cut off. Here, too, the expiratory pressure is often sufficiently powerful to overcome the obstruction, but if under these circumstances it is too feeble, collapse of the lung ensues. When, on the other hand, the inspiration is strong enough to overcome this obstacle, air enters the alveolæ, and, being imprisoned there, causes inflation of the air-cells as in asthma. That collapse of the lung does not occur in the latter disease is due to the fact that the inspiratory act is always sufficiently powerful to overcome the spastic contraction of the bronchioles.

13 A. Biermer, "Ueber Bronchial Asthma," Sammlung klinischer Vorträge, No. 12, Leipzig, 1870.

The air entering the lung during inspiration is pent up by the spastic constriction of the bronchi, which, acting as a valve, admits of its passage in one direction, but impedes its escape during expiration, and thus causes inflation of the air-cells and insufficient aëration. Owing to the distension of the alveolæ the thorax is expanded and the diaphragm forced downward. A tetanic spasm of the diaphragm lasting for hours, such as that which Wintrich describes, and with which he endeavors to explain the descent of that muscle as well as the other symptoms of asthma, is not only improbable, but is contrary to clinical experience. If the diaphragm were thus spasmodically contracted, it would remain fixed in one position, but Biermer has demonstrated that there is more or less rhythmic movement of that muscle even during the paroxysm; but if no movement of the diaphragm were observed, it would still be no proof of tonic spasm of that muscle, as its immobility might be due to other causes. According to Biermer, the inflation of the lungs and their insufficient ventilation afford a satisfactory explanation of the most important symptoms of asthma, as Breuer14 has shown, in his paper on the automatic regulation of respiration through the pneumogastric nerve, that various embarrassments of respiration must be corrected by some suitable modification of the act itself; hence when, as in asthma, the lung is unable to empty itself, the expiratory act must be strengthened and prolonged to overcome the obstruction occasioned by the spasmodic constriction of the bronchial tubes; whereas incomplete filling of the lung would necessitate increased inspiratory effort. According to Biermer, "expiratory dyspnoea is as characteristic of obstruction of the finer tubes," be it from spasm, as in asthma, or from stoppage with viscid mucus or from swelling of their lining membrane, as in bronchitis, as the same condition during inspiration is of narrowing of the larger air-passages—an important point in differential diagnosis to which we shall again have occasion to refer. He is unable to explain the relationship between bronchial spasm and catarrhal hyperæmia of the air-passages, but believes that it may be accounted for as follows: "Either the bronchial fluxion causes the spasm—that is, that there exists between them a causal connection—or the hyperæmia and the spasm are the joint effect of the exciting (centripetal) nerves; in other words, both are due to reflex action."15

14 "Die Selbsterneurung der Athmen durch den N. vagus," Sitzungsbericht der K. K. Akademie der Wissenschaften zu Wien, Bd. lviii. Abtheilung ii., Nov., 1868.

15 In presenting Biermer's theory the writer has drawn freely upon that author's well-known lecture on "Bronchial Asthma," as published in Volkmann's Sammlung klinischer Vorträge, loc. cit.

Another explanation of the phenomena of asthma is that proposed by Lebert,16 who, although he concedes that bronchial spasm is an all-important factor, denies that it of itself is sufficient to account for the sudden and enormous inflation of the lungs observed in that disease. He doubts the possibility of a valvular closure of the bronchi, as claimed by Biermer, but believes that the bronchial spasm, which he regards as primary, causes secondary spasmodic contractions of the diaphragm and of the inspiratory muscles of the neck and chest. The spasm of the diaphragm he believes to be tonic in its character, but not continuous, thus meeting Biermer's objection to the Wintrich theory, that tonic spasm of that muscle lasting longer than a few minutes would inevitably cause fatal asphyxia.

16 Klinik der Brustkrankheiten, 1ster Band, 2te Hälfte, p. 438.

Theodor Weber,17 rejecting the above theories on the ground that neither bronchial spasm nor tonic contraction of the diaphragm is capable of explaining why catarrhal secretion should come on at the close of an attack in which at the commencement there was no catarrh, attributes the phenomena of asthma to sudden swelling of the bronchial mucous membrane, the result of dilatation of its blood-vessels produced through the agency of the vaso-motor nerves; thus reviving the fluxionary theory of Traube. In support of this theory he cites the result of Von Loven's18 experiments, which prove that irritation of the sensory nerves is followed by reflex engorgement of the territory to which they are distributed. Weber considers that this engorgement of the bronchial mucous membrane is somewhat similar to the acute swelling and stoppage of the nostrils to which many persons are subject—a closure which often does not last longer than a few moments, and which is attended with increased redness and swelling of the Schneiderian membrane. The mucous membrane of the nostril and that of the bronchi being both parts of the respiratory tract, and somewhat similar in structure, he concludes that the process in the nostrils is analogous to that which occurs in the bronchi during the asthmatic paroxysm. As additional proof of the correctness of his hypothesis he cites the fact that such occlusion of the nostrils is often the precursor of the asthmatic attack, and in some cases continues throughout the paroxysm. See investigations of Daly, Roe, Allen, and Hack, further on.

17 "Ueber Asthma Nervosum," Tageblatt der 45 Versammlung deutscher Naturforscher u. Aertze in Leipzig, etc., 1872, p. 159.

18 Naturforscher u. Aertze in Leipzig, etc., 1872, p. 159.

The idea that asthma is due to swelling and engorgement of the bronchial mucous membrane appears to have been confirmed by the tracheoscopic observations of Stoerk.19 On examining the air-passages with the laryngoscope, he could see the mucous membrane of the trachea as far as visible (that is, to the bifurcation) grow red with the onset of the paroxysm, and resume its normal appearance after the termination of the attack. He opposes the spasm theory, denies the correctness of Biermer's conclusions, and adopts Weber's explanation of the asthmatic phenomena. He agrees with Wintrich that spasm of the diaphragm occurs, but claims that it results from the tension to which it is subjected by the inflated alveolæ: the diaphragm being forced downward by the distended lung, its fibres are stretched, and the result is a tonic spasm of that muscle. His objections, although well stated, are not sufficiently conclusive to cause us to accept his opinion in preference to that of Biermer and other supporters of the spasm theory.

19 Mittheilungen über Asthma bronchiale, etc., Stuttgart, 1875.

Max Schaeffer maintains that asthma is due to bronchial fluxion, as advocated by Weber, but claims that the hyperæmia is followed by spasm of the bronchial muscles, the former being primary and the latter secondary. He also, with many other recent writers, believes that asthmatic attacks are often associated with pathological conditions in and about the upper air-passages, such as naso-pharyngeal and laryngo-tracheal catarrh, polypi, hypertrophied tonsils, and enlarged cervical glands; all of which act as irritants, which, being transmitted through the neighboring nerves to the vagus, induce the bronchial spasm.

Among the older and discarded theories is that of Bree, who in a work published at the commencement of the present century expressed the opinion that the dyspnoea of asthma was simply an effort on the part of nature to rid the bronchial tubes of an irritating substance supposed to have accumulated in them previous to the attack. He believed that this materia peccans was thrown out with the expectoration which occurs toward the close of the attack. He regarded the violent efforts made by the respiratory organs to expel this offending substance from the bronchial tubes as similar to the tenesmus of dysentery or the painful contractions of the bladder when irritated by a rough calculus. Bree was unable to define more clearly the nature of this offending substance, but of late years another writer, Leyden,20 has discovered in the sputa of asthmatics certain peculiar crystals to the irritating effects of which he attributes the various symptoms. These crystals had been observed previously by Charcot in the blood of leukæmic patients, and subsequently by Neumann in the medulla of the bones of patients who had died of that disease. Leyden describes the expectoration in asthma as tough, grayish-white, and very frothy. Imbedded in a transparent hyaline mass are a number of small bodies, some thread-like, others in the form of little plugs or flakes. Under the microscope these little bodies are found to consist of a mass of brownish cellular detritus containing large numbers of crystals. These are colorless, octahedral in form, with sharp points, and vary greatly in size, some of them visible at once, while others are seen only with the highest powers of the microscope. Their composition has not been determined, but is supposed to be a substance resembling mucin. Leyden's idea is that the sharp points of these octahedral crystals irritate the terminal ends of the pneumogastric nerve in the mucous membrane of the bronchi, and that this irritation, being transmitted to the nervous centre, is reflected back, and thus causes spasm of the bronchial muscles. It seems, however, that these crystals are not peculiar to bronchial asthma, having been also found in chronic catarrh and other affections of the bronchi.21

20 "Zur Kentniss des Bronchial Asthmas," Virchow's Archiv, Band liv., 1871.

21 Not being able to obtain the original paper, the writer is indebted for the greater part of what he has written in regard to the Leyden theory to the treatises on asthma by Knauthe in Eulenburg's Encyclopædie der gesammten Heilkunde, and by Riegel in the work already quoted.

Of the different theories of bronchial asthma which have just been presented, that of Biermer, although unsatisfactory in many respects, offers the best explanation of the pathology and symptoms of that disease.

PATHOLOGICAL ANATOMY.—Bronchial asthma being a purely functional neurosis, the organs involved present no anatomical changes specially characteristic of that affection. It is true that in cases of long standing, in which, owing to oft-repeated attacks, the air-cells have become distended and their walls attenuated, we find the lungs in the condition which will hereafter be described as emphysema, but these, as well as the evidences of chronic catarrh observed in these cases, are due to the secondary affections, and not to the primary disease.

As previously stated, a certain amount of hyperæmia of the mucous membrane of the larynx, trachea, and bronchi may be observed during life with the aid of the laryngoscope; but whether this condition leads to permanent tissue-changes observable after death is exceedingly doubtful.

In the pneumogastric nerve pathologists have as yet been unable to discover, either at its origin or along its course to the lungs, any alteration in structure capable of explaining the phenomena of bronchial asthma.

DIAGNOSIS.—The suddenness of the attacks; the occurrence of the paroxysm usually in the latter half of the night; the slow, labored expiration, with the whistling, wheezing sounds which accompany it; the expectoration of catarrhal sputa toward the close of the attack; the normal respiration and absence of all signs of disease during the interval between the paroxysms,—are the features by which a case of simple uncomplicated asthma may be readily recognized. When these symptoms are present in their integrity in an otherwise healthy subject, there is no difficulty in arriving at the diagnosis; but, unfortunately, the picture is not always complete. The asthma may be complicated with organic disease of the heart or lungs, while primary disease of these organs, as well as certain affections of the nervous system, may produce symptoms closely resembling those of bronchial asthma, and from which it is very essential to distinguish them.

The following are some of the affections which may be mistaken for bronchial asthma:

1. Bronchial catarrh may be accompanied with more or less difficult respiration, but even in its worst forms it never causes the severe attacks of dyspnoea observed in bronchial asthma, and, as Riegel justly remarks, the severity of the symptoms in the latter disease are out of all proportion to the insignificance of the physical changes.

The dyspnoea of bronchitis comes on more gradually, the attacks being dependent upon a variety of accidental circumstances; whereas the asthmatic paroxysm usually occurs quite suddenly in the night without any apparent cause. The cough in bronchitis is severer and the expectoration more abundant than in asthma; the latter is also different in quality, becoming purulent as the disease advances, whereas in asthma it seldom loses its mucous character. These points of difference and the presence of the other symptoms of bronchitis are sufficient to differentiate that disease.

2. Emphysema is frequently associated with asthma, either as a cause, as is believed by many, or as an effect of that disease. It is often exceedingly difficult to determine whether the emphysema when present is the cause of the dyspnoea (symptomatic asthma), or whether the inflation of the air-cells and other symptoms are not the result of the bronchial spasm: a careful inquiry into the history of the case will often decide the question. The points of difference between the two diseases are very similar to those to which we have just called attention as the distinguishing features between the dyspnoea of bronchitis and the true asthmatic paroxysm. The suddenness with which the attack comes and goes, the severity of the symptoms compared with the insignificance of the local lesions, the absence of dyspnoea in the intervals between the attacks (in uncomplicated cases), are all the reverse of what is observed in emphysema. In that disease the attacks develop more gradually; there is always more or less shortness of breath, and the evidences of changes in the structure of the lung are quite marked.

3. Dyspnoea resulting from cardiac disease is often very severe, but may be distinguished from bronchial asthma by the presence of the various murmurs and other physical signs by means of which that class of diseases is recognized. The asthmatic paroxysm, as a rule, comes on when the patient is most quiet, usually during sleep. The attack of cardiac dyspnoea, on the contrary, is always brought on or aggravated by physical exertion, mental excitement, or some other apparent cause. In asthma the respiration during the intervals between the paroxysms is quite natural; in cardiac dyspnoea there is always more or less embarrassment. Pain in the region of the heart, in many cases quite severe and extending down the left arm, may direct attention to that organ as the source of the dyspnoea.

4. Spasm of the glottis, croup, oedema of the glottis, tracheal stenosis, are all attended with more or less violent attacks of dyspnoea. We are indebted to Biermer for having directed attention to an important symptom by means of which all these affections may be distinguished from bronchial asthma. In the latter, and in all other diseases causing narrowing or obstruction of the finer bronchi, the dyspnoea is during the expiration, but if the impediment be in the larger air-passages the dyspnoea will be during the inspiration. "Dyspnoea during expiration is just as characteristic of narrowing of the finer bronchi as the same condition during inspiration is of croup and other forms of laryngeal stenosis." In croup the neck is extended and the head thrown back. Notwithstanding the violent inspiratory efforts of the patient, the lungs are but partially filled; the air in them becomes rarefied, causing a yielding of the less-resisting parts of the thorax—e.g. the supraclavicular space, the lower portion of the sternum, and adjacent costal cartilages—and a sinking in of the abdomen. During expiration, which is accomplished quickly and with comparative ease, the thorax resumes its natural form. In bronchial asthma, on the contrary, the head is thrown forward, and the shoulders fixed in such a position as to enable the muscles of expiration to work to the best advantage. The thorax, instead of sinking in, is expanded and abnormally round, giving on percussion the peculiar pasteboard-box sound (Schachtelton) which Biermer has described as characteristic of inflation of the alveolæ. In croup the sibilant râles are heard during inspiration, while in asthma they are more pronounced during expiration.

5. Spasm of the diaphragm is another affection from which it may be necessary to distinguish bronchial asthma. This rare disease, which is almost always associated with hysteria, is characterized by a short inspiratory movement, during which all the muscles of inspiration are brought into action, and we have the same sinking in of the more yielding portions of the thorax which has just been mentioned as one of the distinguishing features of laryngeal stenosis. After this the thorax remains fixed for a few seconds, the muscles of inspiration remaining in a state of contraction. There then ensues a quick and powerful expiratory effort, accompanied by a sound not unlike that of hiccough; then another inspiration, with a repetition of the above symptom; and so on until the attack is over. It will be seen from this description that this affection resembles singultus more than asthma, and that there is but little likelihood of its being mistaken for the latter disease.

6. Paralysis of the posterior crico-arytenoid muscles, like croup, spasm of the glottis, and all other affections which produce narrowing of the larger air-passages, is distinguished by the dyspnoea being inspiratory, and not expiratory. The function of the posterior crico-arytenoid muscles being to enlarge the glottis, the result of their being paralyzed would be to lessen the opening through which the air passes to reach the lung; and in viewing the cords in such a case with the laryngoscope it will be found that the opening is reduced to a narrow chink. Another distinguishing feature is that the dyspnoea is continuous, and, unlike bronchial asthma, does not come on in paroxysms.

7. An affection which, like asthma, comes on in the night during sleep is the condition known as nightmare, and, like the former disease, is characterized by labored breathing. To distinguish it, it is only necessary to awaken the patient, when the immediate cessation of all symptoms will at once remove all doubt as to the nature of the affection.

8. Through carelessness or ignorance intercostal neuralgia has been sometimes mistaken for asthma. Pain along the course of the nerve and the presence of the points douloureux, which Valleix has described as characteristic of neuralgic affections, are sufficient to establish the diagnosis.

9. Embolism of one of the middle or larger branches of the pulmonary artery is also characterized by great embarrassment of respiration, but is not likely to be mistaken for asthma by any one at all familiar with the two affections. The cachectic appearance of the patient, the intense anxiety depicted on his countenance, the evidence of cardiac disease or of some affection of the vessels, the weakened cardiac impulse, the thready and at times irregular pulse, together with evidences of more or less pulmonary oedema, are sufficient to distinguish this form of dyspnoea from that of asthma.

PROGNOSIS.—As there is no well-authenticated case of death from uncomplicated asthma, the prognosis quoad vitam may be regarded as absolutely favorable. That death never occurs during the severe paroxysms of asthma may be due to the action of the deficiently aërated blood upon the respiratory centres, and bronchial spasm, causing relaxation when the symptoms have become most threatening. The asthmatic, if his case be incurable, may live for a number of years, and even attain to extreme old age, but his life will be one of intense suffering, which becomes more intolerable as he advances in years. Sooner or later, bronchitis, emphysema, or heart disease is developed, which in its turn may lead to renal disease and dropsy.

Such is the almost invariable result in middle-aged and elderly persons; in the young, however, the chances of recovery are much more favorable. Salter22 states "that in youth the tendency is invariably toward recovery, whereas in one attacked with it after forty-five the tendency is generally toward a progressive severity of the disease and the production and aggravation of those complications by which asthma kills." The favorable result in childhood he attributes to the recuperative power of youth: growth and change, being more rapid than later in life, enable the system to repair during the intervals whatever damage may have been sustained during the paroxysms.

22 On Asthma, Am. ed., p. 168.

There is another class of cases in which, owing to our being able to recognize and remove the cause, the prognosis is quite favorable: thus, if it has been discovered that the disease is due to some local influence, change will often effect a cure, and the patient will remain well as long as he remains in the locality which agrees with him, but generally relapses if he ventures to return to the place where he first contracted the disease. The same may be said of that form of asthma in which the disease is due to some trade or pursuit necessitating the inhalation of irritating dust or gases: the indications are obvious. Cases in which the paroxysms have been traced to the presence of nasal polypi or to a tumor pressing upon the course of the pneumogastric nerve have been promptly cured by the removal of these growths. In all these cases it is presupposed that there is no organic disease, for the presence of any one of the serious complications we have mentioned would dissipate all hope of cure.

In arriving at a prognosis it is all-important to inquire into the severity and frequency of the attacks, as violent paroxysms at short intervals soon lead to incurable complications. It is also essential to ascertain the condition of the patient during the intervals between the paroxysms: if at that time he feels well and does not suffer with shortness of breath, we may infer that as yet no organic change has occurred; if, however, he complains of more or less dyspnoea during the intervals, we may safely conclude that some organic disease has set in and that the case is incurable. Salter attaches great importance to the persistence of expectoration during the intermissions, regarding it as indicative of bronchitis, and therefore as an unfavorable indication: to use his own words, "Spitting is one of the worst signs in asthma."

Briefly, those cases may be regarded as favorable in which the patient is young and has no inherited tendency to the disease, is free from the many complications of asthma, and in whom the attacks are light and occur at long intervals. On the other hand, all cases may be regarded as unfavorable in which the patient has reached or passed the middle period of life, has inherited a tendency to asthma, if the attacks are severe with short intervals, or if he has some one or more of the secondary affections of the disease.

TREATMENT.—The treatment of bronchial asthma consists of measures to mitigate and relieve the paroxysms and prevent their recurrence.

A. Of the Paroxysm.—A patient suffering with an attack of asthma will generally instinctively assume the position in which he can use the muscles of respiration to the greatest advantage, but if found in the recumbent posture he should be advised to sit up in bed and grasp the knees with his hands, so as to gain a position which admits of the more ready entrance of air into the lungs. In severe cases it is better to have him rise from the bed and support the head with the hands, the elbows resting on a table in front of him. An ingenious suspension-apparatus, intended to promote the comfort of persons suffering with severe dyspnoea, was extensively advertised several years ago, and may possibly still be furnished by the instrument-makers. It consists of a cross-piece suspended from the ceiling, to which straps are attached for supporting the shoulders without in any way pressing upon the chest; it is also provided with a band for the support of the head. In severe and protracted cases, when, notwithstanding the patient's exhaustion, he is unable to rest upon pillows, such an arrangement might afford great relief. If not undressed, the clothing should be so arranged as to interfere as little as possible with the respiratory movements. An abundant supply of fresh air is essential, and to secure this one or more windows should be thrown open.

Asthma being the most capricious of diseases, remedies often acting differently in each individual case, it is well before commencing treatment to follow Salter's advice and inquire of the patient what remedy has usually afforded the most prompt relief in previous attacks, and thus avoid the risk of prolonging suffering by using remedies which, although apparently indicated, may in his case, owing to peculiar idiosyncrasies, prove to be useless or even injurious.

We have seen that the disease is often due to some special cause, such as the inhalation of an atmosphere laden with the perfumes of certain flowers, with ipecac, dust, etc., the removal of which, if practicable, should of course precede all attempts at treatment. The condition of the stomach and bowels should be inquired into, and if found overloaded they should at once be relieved, the one by an emetic and the other by enema.

In the absence of any hint afforded by the previous experience of the patient the choice of the remedial agent will depend upon the severity of the attack. In the majority of cases, when severe, no remedy will afford such prompt relief as the subcutaneous injection of morphia. To be effective, the dose should be a full one, a fourth to a third of a grain, either alone or, if there is likelihood of this occasioning nausea, combined with one one-hundredth to one-eightieth of a grain of sulphate of atropia. The writer is aware that the use of opium and other hypnotics in bronchial asthma is discouraged by one of the most distinguished authorities on that disease, Salter, who claims that they are not only worthless, but often injurious. He believes that sleep tends to promote the paroxysm, reflex action being much more active then than during the waking hours, and that any agent which induces such a condition is necessarily contraindicated—that, in his opinion, in addition to exalting reflex action, it acts prejudicially, as "by lowering sensibility it prevents that acute and prompt perception of respiratory arrears which is the normal stimulus to those extraordinary breathing efforts which are necessary to restore the balance." These objections, although supported by scientific evidence, are insufficient to cause the abandonment of an agent which in the hands of others has proved so prompt and efficacious in relieving the terrible sufferings of asthma, and Salter himself admits that since writing the above he has had cases in which it has been of signal service. A serious objection to its use is that the dose has to be increased as the patient becomes accustomed to its use. In confirmation of its marked beneficent effects, I give the following extract from Steavenson's treatise on asthma. Describing his own experience, he says:23 "Sedatives and antispasmodics I should consider most serviceable drugs, but above all in value I should place the hypodermic injection of morphia. This has never failed to relieve an attack in myself, and I have never seen it fail in other patients. The objection to it is that if often used the dose must be increased; but it is better to increase the dose of morphia than suffer the agonies of asthma and allow those organic changes in the constitution to take place which I have described when speaking of the pathology of the disease. I have now used morphia for five years, but my attacks are so quickly relieved and so reduced in frequency that I have never yet had to increase the dose I commenced with—namely, one-sixth of a grain."

23 Op. cit., p. 29.

Having administered the morphia, other measures for the relief of the patient should be resorted to. The feet and hands should be immersed in hot water to which a small quantity of mustard has been added. Dry cups between the shoulder-blades or sinapisms over the chest or epigastrium often afford marked relief.

If, on account of the existence of an idiosyncrasy on the part of the patient or from other causes, opium cannot be employed, we have in chloral hydrate a substitute which is almost as efficacious and perhaps even more prompt. Next to morphia, it is the most valuable remedy, and many esteem it superior to that drug, over which it possesses the advantage of not being followed by the disagreeable effects which so often succeed the administration of opiates. It should be given in doses of thirty or forty grains, and repeated if the paroxysm does not yield.

The inhalation of chloroform has long been esteemed as a potent agent in overcoming the bronchial spasm. One would naturally suppose that the use of such a powerful sedative as chloroform would be a dangerous proceeding in a disease which, like asthma, is attended with so much embarrassment of respiration and circulation; but experience does not justify this fear, and Salter, who has used it with good effect in 12 out of 13 cases, assures us that he has administered it "in the very agony of the worst attacks; that, so far from fearing it under such circumstances, it has been able to relieve the intensest asthma that nothing else would reach; that he has given it, and that he has never seen any bad effects from it." He goes on to state that as chloroform relaxes the bronchial spasm, and thus removes the cause of the "asphyxial stoppage, the intensity of the apnoea, so far from being a reason against the administration of chloroform, is the great reason for its immediate employment." He considers neither muscular weakness of the heart nor valvular disease as any contraindication to its administration, provided the circulation is not materially affected. According to Stokes, the paroxysm is not entirely suppressed by chloroform, but returns as soon as the patient passes from under its influence; hence it must be repeated as occasion may require. It should always, if possible, be given at the commencement of the paroxysm, and should never be allowed to produce complete insensibility, nor should so seductive a remedy be left in the hands of the patient. The danger of the self-administration of chloroform is only too well attested by the frequent accounts in the journals of persons found dead in their beds from the effects of that agent, death in such cases being usually due to the patient's unconsciously leaving the handkerchief over the mouth and continuing to inhale the chloroform after having become insensible. When given sufficiently early, a few whiffs may be all that is necessary to overcome the paroxysm; and this repeated as soon as it threatens to return, will often enable us to control the symptoms without resorting to larger quantities.

An old and still very popular treatment—said to have been introduced by an American, Nicholas Frisi,24 in 1843—consists of the inhalation of the fumes of burning saltpetre or in smoking cigarettes made of paper which has been soaked in a saturated solution of that substance. Inhaled into the bronchi, it is supposed to act as an anæsthetic, and produces relaxation of the constricted bronchial muscles. In point of efficiency these inhalations rank quite high, and are probably more generally used than any other remedy. Aside from the relief which they undoubtedly afford, this method derives much of its popularity from being within easy reach of the patient himself. The preparation of the papers is exceedingly simple: A sheet of bibulous paper is dipped into a saturated solution of the nitrate of potassa prepared with cold water; after drying it is divided into strips of the size required. These papers are burnt before the patient, the windows and doors of the apartment having been previously closed to prevent the escape of the fumes. Nitrate of potassa has been prepared in a variety of other ways for the use of asthmatic patients, one of the most convenient of which is the Kidder pastilles so extensively used in this country. Another method is to roll the paper prepared as above into cigarettes, the smoke of which is inhaled by the patient. The nitre is best used early in the attack, but is also beneficial when the paroxysm is at its height. The efficacy of this treatment is attributed by Germain Sée to the formation of protoxide of nitrogen and carbonic acid gas, which act as an anæsthetic, and perhaps also to the particles of carbon in the smoke floating in the air, a smoky atmosphere being beneficial to many asthmatics.

24 Germain Sée, op. cit., p. 709.

The smoking of the Datura metel having been found efficacious in asthma in India, Anderson of Madras in 1802 sent some of the leaves to Gen. Gent, an English officer, by whom they were introduced into England. Simms of Edinburgh, believing that the Datura stramonium might prove equally good, tested it with such good results that it soon came into general use, not only in asthma, but in other forms of dyspnoea. This is the ordinary Jimson or Jamestown weed which is so widely distributed over the Southern, Middle, and Northern States, and, like nitrate of potassa, is much used, not only by the profession, but largely as a household remedy for asthma. The dried leaves are either smoked in a pipe or in the form of a cigarette. The effects, however, are quite uncertain, sometimes acting like a charm, while at others it affords no relief; its physiological action is that of a sedative. Of late years another species of Datura has been introduced—the Datura tatula. Its properties and uses are similar to those of stramonium, but it is supposed to be less narcotic.

Belladonna and its alkaloid, atropia, are often used in the treatment of asthma, but their action is uncertain and often unsatisfactory. The three last-mentioned remedies are also used in combination, as in the well-known Espic cigarettes, the formula for which, according to Trousseau, is as follows, viz.:

Rx.Fol. belladonnæ,gr. vj;
Fol. hyoscyami,gr. iij;
Fol. stramonii,gr. iij;
Fol. phillandrii aquatic.gr. j;
Ext. opii,gr. ¼;
Aq. lauroceras,q. s.

The leaves, after being cut up, should be thoroughly mixed, after which they are moistened with the cherry-laurel water, in which the opium has been previously dissolved. The wrapper of the cigarette is also soaked in the same solution and dried. One or two of these cigarettes should be smoked during the attack. Abbott has been very successful with belladonna applied as a spray (drachm j of the extract to one ounce of water) when the spasm threatens.

Tobacco is a powerful depressant, and in those who are unaccustomed to its use is an invaluable remedy in asthma. In the uninitiated it excites nausea, vertigo, cold sweats, and other symptoms of relaxation which Salter not inaptly compares to those of sea-sickness. "The moment this condition can be induced the asthma ceases, as if stopped by a charm." It may, however, be asked whether the remedy is not worse than the disease. Those who retain a vivid recollection of the horrible consequences of their first smoke will hesitate before prescribing tobacco for one unaccustomed to its use. There are many who, not wishing to lose the beneficial effect of tobacco in asthma, never smoke unless a paroxysm threatens.

Lobelia, like the above also a depressant in its action, was formerly much employed in asthma. It is still used, but its effects are disagreeable and by no means certain.

The intimate nervous connection which exists between the lungs and stomach would naturally lead us to anticipate good results from emetics. In asthma, as in laryngismus stridulus, an emetic often affords prompt relief and arrests the paroxysm. The nausea which precedes the act of vomiting, acting as a depressant, causes relaxation of the spasm, while the emesis by unloading the stomach removes an important source of irritation. Like tobacco and lobelia, remedies of this class are only beneficial when pushed far enough to produce the symptoms of depression and collapse to which we have alluded; these once established the relief is usually complete. Tartar emetic and ipecacuanha are the representatives of this class most used in asthma. Tartar emetic, owing to the excessive and long-continued depression which it occasions, is now rarely employed, having been almost entirely superseded by ipecacuanha, which is equally efficacious and more prompt. Its effects also disappear more rapidly than those of antimony. Like other remedies intended to cut short the paroxysm, ipecacuanha should be given as early as possible. It should be taken in full doses of at least twenty grains.

Bromide of potassium, as is well known, acts upon the vaso-motor nerves, causing contraction of the arterioles of the brain and spinal cord, and thus inducing a state of partial anæmia which results in a lessening of the irritability of these organs, quieting muscular spasm and inducing sleep. These effects would naturally lead to its employment in spasmodic asthma. Although occasionally used with success in shortening the paroxysm, it is better adapted, as suggested by Riegel, for use during the intervals, when, if given continuously, it sometimes diminishes the severity of the paroxysms and causes them to recur less frequently.

Nitrite of amyl, a most valuable addition to our materia medica, has been extensively used in the treatment of asthma, but the reports of the results attained are too contradictory to admit of our forming any just estimate of its merits. The general opinion is that it relieves the dyspnoea and makes the patient for the time being more comfortable; and this accords with my own experience. The usual method of administration is to drop one or more minims upon a handkerchief and to inhale the vapor. It is also used internally, and, in the single case that has come under my observation, with benefit. The following case, reported by Pick and cited by Riegel,25 is instructive as showing the favorable effects of nitrite of amyl: "The case was that of a medical student who from his youth onward had suffered with asthmatic troubles, which increased as he grew older and had proved rebellious to all remedies. Nothing except expectorants and narcotics afforded him the slightest amelioration of his symptoms. On inhaling nitrite of amyl he experienced immediate relief, which lasted for some time after the inhalation. He was enabled to breathe deep and with comparative ease. The relief afforded was but transitory, but, on the other hand, was so sure that the patient resorted to it whenever the attack came on." The same writer reports two other cases in which he succeeded by means of nitrite of amyl in relieving the paroxysms and in increasing the interval between them.

25 Op. cit., p. 295.

More agreeable to the taste and at the same time more effectual than the potassium iodide is hydriodic acid. It is best administered in the form of a syrup, preferably that prepared by Gardener of New York.

Salter, who appears to have had more experience with alcohol than any other writer, narrates the case of an elderly Scotch lady who, having exhausted all the known medicines and other agents used in asthma, was finally relieved by full doses of whiskey. This was invariably successful, but the dose, of course, had to be increased as the disease grew older. He also mentions another case in which nothing except chloroform afforded any relief. This he describes as the severest he has ever witnessed. "I have never seen or heard of spasms so violent or that seemed so nearly to put life in peril. His most intense spasms he calls 'screaming spasms,' from the strangling cries that the want of breath compels him to make. At the time of which I am speaking he lived on the same street with myself, and, although his house was half the length of the street from mine, his nurse has often assured me that if the doors had been open I could have heard his screams at my house at night. All remedies except the chloroform had failed, when one day his nurse advised him to try brandy. It afforded him almost instantaneous relief. He took enormous quantities of it, the first day a quart, and in the course of two months as much as twelve gallons. The spasm invariably stopped as soon as he took it, and for the last five months that he was under observation he had only what he called a 'thickness, a tight, constricted breathing,' several times during the night." Salter is particular in stating that the brandy should be given strong and hot.

Another stimulant highly recommended by Salter is coffee. In stating his objections to the use of opium it will be remembered that one of his reasons for not availing himself of that remedy was that it caused sleep, and that the exaltation of reflex action in that state favored the asthmatic paroxysm. Coffee, being a strong excitant of the nervous and vascular system, has the contrary effect and keeps the patient awake. It should be prepared as a strong infusion without the addition of either sugar or milk and given some time before the expected paroxysm. Administered in this manner, he claims that coffee will relieve two-thirds of all cases of asthma. The relief afforded is, however, very unequal, being in some cases complete, while in others it is only slight and transitory.

Quebracho in the form of an extract has been much used of late years in the treatment of asthma and other affections attended with dyspnoea. It has been found quite useful in mild cases.

The induced electrical current has been recommended by Schaeffer as a means of cutting short the paroxysm. His method is to place one pole on either side of the neck immediately below the angle of the jaw and in front of the sterno-cleido-mastoid, so as to cover the course of the pneumogastric and sympathetic nerves. The current should be sufficiently strong to enable the patient to feel the passage from one side of the throat to the other. It is applied for fifteen minutes twice a day for six days, twelve sittings being usually sufficient to afford relief. When the current is first applied it not infrequently causes dilatation of the pupils, but this is succeeded by contraction when the treatment begins to manifest its beneficent effects.

B. During the Intervals between the Paroxysms.—The diet and daily regimen of the asthmatic should be most carefully regulated, the best and most skilfully directed treatment being of little avail if these important matters are neglected.

The asthmatic patient should be encouraged to pass much of his time in the open air, but the amount of walking he should do will of course depend upon his strength and freedom from secondary affections of the heart and lungs. In a case of simple uncomplicated asthma the more the patient walks the better he will feel; but this is not to be construed to mean that he is to walk until exhausted; on the contrary, his walks should at first be quite short, proportioned to his strength and wind, and then gradually extended, but under no circumstances should he be allowed to overfatigue himself. With a view to keeping the skin in the best possible condition the body should every morning be sponged with water, the temperature of which must be suited to the condition of the patient. If he be feeble and anæmic, the water should be tepid, but whenever admissible cold is to be preferred. After the bath it is essential that the skin be thoroughly rubbed with a coarse towel until it becomes slightly reddened. The cold bath properly used not only invigorates the system generally, but by enabling the body to stand the vicissitudes of temperature diminishes the risk of the patient's taking cold.

The intimate relations existing between the lungs and stomach, and the fact that asthmatics usually suffer at the same time with dyspepsia, make the question of diet an all-important one. Their meals should consist of good, nutritious food, rigidly excluding all heavy, indigestible substances, such as cheese, nuts, dried fruits, etc. The meals should be taken at regular hours, and, as asthma almost always comes on at night, it is important that the principal repast should be in the morning or early part of the afternoon, and that any food taken between that and the hour for retiring should be of the lightest possible description. The more empty the patient's stomach, the better will be the chances of his passing a good night. Alcoholic drinks, coffee, and other stimulants should only be allowed when prescribed as medicines, as they have a tendency to aggravate the hyperæmia of the air-passages, which is one of the prominent features of the disease. Constipation should of course be carefully guarded against.

Aside from the apparently well-established fact that asthmatics do well, and often remain so, in the damp, foggy air of crowded cities, we have no means of determining beforehand what locality will suit a case of asthma. Change of climate in such cases is a mere matter of experiment, but when such change is determined upon the patient should at first try a place which is in every respect the reverse of the one he has previously lived in. If his former residence was in a city, he should remove to the country; if the old place was dry, the new one should be damp; if he has lived in a flat, low country, let him try the mountains; and vice versâ. As already stated, removal from the pure air of the country to the foul, smoky air of a city densely populated often affords complete relief, but so soon as the patient returns to his old home the asthma reappears and is as bad as ever.

As regards its capriciousness as to locality, I quote the following interesting case from Salter's work on asthma: "G. C——, a confirmed asthmatic, a native of a city in Scotland in which he resided, having been a sufferer for many years, came to London in 1838 for the sake of receiving the best medical advice. He took apartments in the centre of the city of London, somewhere near St. Paul's. His intention was to wait for an attack, and as soon as one came on to present himself to his physician, that he might witness it and have a clear idea of the state he was in. He waited six weeks, much to his mortification, not only without experiencing one, but without any difficulty of breathing whatever. His health altogether improved; he slept well and gained flesh. Being tired of waiting, he went back to Scotland without having seen his physician at all, and, to his great disappointment, he had not been in his native city many days when he was attacked in the usual way, and continued to suffer just as before his visit to London. Subsequently, finding it necessary on matters of professional business frequently to visit London, he experienced the same result on all occasions as at his first visit—perfect immunity from his disease. To use his own expression, 'he felt in London like a renewed man.' On his first arrival in town he was in a miserable state: he could not move without feeling his shortness of breath distressingly; he got no rest at night, and was seldom able to lie down in his bed. But in London he could do anything—eat, drink, sleep. The consequence was he gained flesh and strength, and went back to Scotland looking quite a different man. This was the invariable result."

Having once found a place which agrees with him, the asthmatic should remain there, as change of climate when no good is effected often does harm.

Arsenic has long been a favorite remedy in asthma, and is undoubtedly of great value in a number of cases. It was used in the form of a vapor by Dioscorides, and, notwithstanding its poisonous properties, has always occupied a prominent place in the therapeutics of diseases of the air-passages. In Styria and other parts of Lower Austria arsenic is habitually eaten by many of the peasants to enable them to breathe more readily while climbing over their elevated mountains and to endure the fatigue incidental to their long pedestrian journeys. The same habit is said to prevail in China, where, however, it is not taken internally, but is smoked mixed with tobacco. Its physiological effects are thought to be due to the increased oxidation of the blood which it promotes, as is proven by the great increase of urea observed after its administration. The blood thus oxygenized stimulates the vital centre, and thus the nerves and muscles of respiration are incited to increased activity, as a result of which the respirations become freer and more easy. Those who believe in the herpetic diathesis derive an additional indication for its administration from the good effects which it manifests in cutaneous diseases. It is best administered in the form of liquor potassii arsenitis (Fowler's solution), giving at first only three drops in a wine-glassful of water after each meal, and increasing the dose one drop each day until the patient takes thirty drops in twenty-four hours. Should any toxic symptoms supervene—pain in the stomach or diarrhoea, puffiness of the lids or redness of the conjunctiva—the arsenic should be at once suspended, and not resumed until they shall have subsided. Thus given, it is quite safe. Trousseau recommends its use in the form of cigarettes, which are prepared as follows: "Twenty grains of the arsenite of potassium are dissolved in half an ounce of water, and a sheet of bibulous paper soaked in this solution until it is all taken up. The paper is then dried and divided into twenty equal pieces, which therefore contain one grain arsenite of potassium each. Each paper is then rolled in the form of a cigarette. In smoking them the patient should endeavor to inhale the smoke into the bronchi. He should take only four or five whiffs once a day."

Iodide of potassium often affords most satisfactory results in the treatment of asthma, but in many cases it fails entirely. It is a drug which must be given for a long period at a time, occasionally for weeks, before it manifests its effects, and want of perseverance may account for its failure in many cases. It forms one of the chief ingredients in Aubrée's antiasthmatic elixir, the formula for which is somewhat uncertain. According to Trousseau, it is as follows:

Rx. Rad. polygalæ, gr. xl;
Coque c. aqua fervida, ounce iv ad ounce ij;
Filtrat, adde Potass. iodid. drachm iv;
Syrup, opii, ounce iv;
Spts. vin. gallic. ounce ij;
Tr. coccionellæ, q. s. ad coloraud.
Filtra.

Of this Trousseau states three tablespoonfuls are taken "in the morning fasting, at noon, and in the evening, until the asthma disappears." Each dose contains no less than forty-five grains of the iodide of potassium and four-fifths grain of extract of opium. Aubrée himself always insisted that each dose should be followed by a "tablespoonful of chocolate pastille, which neutralizes the irritating action of the iodide of potassium."26

26 Trousseau, op. cit., p. 656.

A remedy resembling in its effects the one just mentioned is nitro-glycerine. It is administered in the form of a one per cent. alcoholic solution, in doses of half a drop, increased to three should the smaller dose prove inefficient. Its effects manifest themselves in from three or four minutes to a quarter of an hour, and disappear within an hour after its administration. The dose should be increased with great caution, as a single drop of the above solution has been known to produce alarming symptoms. The euphorbia pilulifera, much lauded by Australian physicians for its wonderful effects in bronchial asthma, promises to rank as an invaluable remedy in the treatment of that disease. It is best administered in the form of a decoction prepared by steeping one ounce of the fresh, or half that quantity of the dried plant, in two quarts of water, and simmering it down to one quart. The dose of this decoction is three or four wineglassfuls during the day, the last dose preferably in the evening, after supper.27

27 Boston Medical and Surgical Journal, 1885, p. 66.

Leyden, whose theory has been mentioned elsewhere, has proposed a new treatment based upon the solubility of the Charcot crystals in chloride of sodium and carbonate of sodium. A solution of one part of these salts in one hundred parts of water should be inhaled twice daily in the form of a spray.

Oxygen has often been used in asthma, but is now seldom administered except in cases associated with great anæmia.

Sée gives the following statistics of the results of the treatment with compressed air in asthma and its secondary affections. Bertin used it in 15 cases of emphysema, all of which he cured, and in 92 cases of nervous and catarrhal asthma with emphysema, of which 67 were completely and 22 partially cured, while it was only unsuccessful in 3 cases. Of Sandahl's 77 cases of asthma with emphysema and bronchitis, 57 were much relieved, and of 14 uncomplicated cases, all were completely relieved. Compressed air may be applied either by placing the patient in a pneumatic cabinet or by means of the portable apparatus of Waldenburg. It must be remembered, however, that in the cabinet the compressed air acts upon the whole body, while in the portable apparatus only the air-passages and alveolæ are subjected to pressure; hence if the latter is used the amount of pressure must be considerably diminished. Notwithstanding the success claimed for this method of treatment, it should be used with caution, and if the case is complicated with emphysema it should either be regarded as contraindicated, or, if employed, the pneumatic cabinet should be used and not the portable apparatus. In the former, or "air-bath," the exterior pressure of the compressed air acts as an auxiliary to "the elasticity of the thorax and to the abdominal gases in" expiration, and at the same time, by compressing the vessels outside the thorax, aids the venous circulation. The same force exercised on the inner surface of the tubes tends to lessen the hyperæmia of the bronchial mucous membrane (Moeller).28 When the portable apparatus is used, expiration in rarefied air causes retraction of the thorax, and thus in a measure overcomes any tendency to emphysema. A better plan than to use either singly is to combine the two—to expire into rarefied and inspire compressed air—which may be readily accomplished with several of the improved portable apparatuses.

28 Thérapeutique locale des Maladies de l'Appareil respiratoire, Paris, 1882, p. 283.

The inhalation of sulphuretted hydrogen as practised at Eaux Bonnes, Cauterets, Aix-la-Chapelle, and other sulphur baths, is said to have cured some cases, while in many others great benefit is claimed to have been derived from its use; but allowance must be made for exaggeration in many of the reports published.

In giving the treatment of asthma no allusion has been made to Grindelia robusta and other recently-introduced remedies, partly because the writer has had no experience with them, and again where he has tried them they have given negative results.