In our own times, a work characterised by singular arrogance and sophistry, has appeared from the pen of Dr. Charles Maclean,[[179]] the object of which is to shew that “a belief in the contagious nature of the Plague constitutes one of the most destructive errors in the whole circle of human opinions;” in the very commencement of this work he betrays an ignorance which is not uncommonly associated with that species of unbecoming confidence, which so strikingly characterises the writings of this author. “It is unequivocally ascertained,” says he, “that the doctrine of contagion, as the cause of epidemic diseases, was unknown to the ancient physicians; by whom these maladies were expressly attributed to the air:” and he then proceeds to state that the prevalent notion of contagion being an inherent quality of pestilential fever, is derived from a Popish plot of the sixteenth century; an assertion which has not even the merit of originality[[180]]. Hippocrates and Celsus do not certainly take any notice of the subject of contagion; but Aristotle, Thucydides, Livy, Virgil, Lucretius, Ovid, Galen, and Arctæus all contain passages which prove most unequivocally their belief in the contagious nature of Epidemics; the limits of this work will not allow us to be prodigal in illustrations, we must therefore refer the reader to a very interesting memoir upon the subject by Dr. Yeats. (Journal of Science and the Arts.) With respect to the work of Dr. Maclean we would further observe, that he has artfully brought together all those facts which are calculated to afford any support to his doctrine, while he has so ingeniously tortured those that make against it, as to disguise their force and true bearings. Mr. Tully[[181]] has lately furnished the public with some striking instances of the total want of candour with which Dr. Maclean pursued his researches, but the fact is that he determined on the Plague being non-contagious long before he ever visited those countries where it prevails; and hence all the advantages which he possessed, and the opportunities of investigation which his residence in the Levant afforded, have not contributed one fact to the elucidation of the subject, but have, on the contrary, thrown additional obstacles in the path of the honest inquirer.—What can be the organization of that man’s mind, who goes into the Greek Pest Hospital at Constantinople, and, according to his own statement, is attacked on the fifth day after he entered it, with the Plague, and yet continues to assert that the malady is non-contagious?
To Dr. Maclean, however, the medical world are certainly greatly indebted, for had not his Researches been published, it is more than probable that the question of Contagion would not have received the many able elucidations which the experience and science of this country has since afforded it:[[182]] nor would an opportunity have occurred by which the most eminent physicians, and those practically acquainted with the malady, could have delivered a viva voce opinion before a Committee of the House of Commons.[[183]] It may be thought extraordinary that a work, so unphilosophical as that to which we allude, should have created so strong a public sensation; but when we consider the eagerness with which mankind seize any circumstance, however weak, that points towards the removal of burdens under which they are suffering, we shall cease to feel surprised that a work of such bold, and promising assertions, should have soon found its way, through commercial channels, to the table of the Privy Council; nor is it strange that government, naturally anxious to relieve commerce of unnecessary burdens, should have instituted an inquiry to ascertain whether Quarantine regulations were actually necessary, and how far they might be relaxed with safety to the country. A report was accordingly requested from the College of Physicians; who, in order to meet the wishes of the government, appointed a committee from their own body to undertake the requisite examination; it is almost unnecessary to state the conclusion at which they arrived; their report is virtually included in that of the Committee of the House of Commons (for which see Appendix, p. 185.) With respect to the contagious nature of those fevers which have lately committed their ravages in these dominions, especially in Ireland, the proofs appear to be so satisfactory and evident, that we question the stability of that man’s mind who can doubt, and still more who can deny it. But although the question of contagion as relating to certain epidemics appears to be firmly established, we are by no means insensible to the difficulties and anomalies with which the subject is embarrassed; several of which are so important in relation to Police legislation, that we feel it necessary to offer a few observations upon each of the following questions, and which appear to include all the leading points of controversy.
I. Are all Epidemic Fevers contagious?
II. Does the matter of Contagion require the aid of a certain state of the air (Pestilential constitution) to give effect to its powers, and propagation; and to what causes is the decline and cessation of a contagious pestilence to be attributed?
III. Can filth and animal putrefaction generate contagion?
IV. Can a Fever produced by fatigue, unwholesome food, &c. be rendered contagious in its career by animal filth, impure air, &c.
I. Are all Epidemic Fevers contagious?
It has been maintained by Cleghorn[[184]], Hamilton[[185]], Clark[[186]], and Fordyce[[187]], that all fevers are naturally contagious; a position which, if less mischievous in its tendency, is equally erroneous in principle, as that which rejects the doctrine of contagion altogether. It is most probable that none of those fevers which are produced by marsh miasmata are ever propagated from one individual to another by contagion; ample evidence of this truth is afforded by the writings of Dr. James Lind[[188]], where it appears that the most malignant and fatal species of fever have been contracted on shore, but which had never been communicated to the ship’s company. Dr. Trotter[[189]] also says, “in a voyage down the coast of Guinea, in the Assistance, in the year 1762, we had scarcely a man indisposed. We wooded and watered at the island of St. Thomas, and with a view to expedition, a tent was erected on shore, in which the people employed on these services were lodged during the night. On the middle passage every man who slept on shore died, and the rest of the ship’s company remained remarkably healthy.” For similar facts see Medical Observations and Inquiries, vol. iv, p. 156; Clarke’s Observations on the Diseases which prevail in long Voyages to Hot Countries, p. 124; and Dr. Robertson’s Meterological and Physical Observations, &c. 4to, p. 32, 33, and 98. And in connection with this subject, it becomes our duty to offer a few remarks upon the nature of that peculiar Epidemic, called The Yellow Fever.[[190]] Its doubtful affinity with bilious intermittent and remittent fevers, has furnished a subject for keen controversy; and while its contagious quality has been pertinaciously maintained by one set of Physicians,[[191]] it has been as warmly denied by others. The malady has raged repeatedly as an Epidemic in the United States, and was considered for some time as Endemic to that country. “The interests of humanity,” says Dr. Rush,[[192]] “are deeply concerned in the admission of the rare and feeble contagion of the yellow fever, and Philadelphia must admit the unwelcome truth sooner or later that the yellow fever is engendered in her own bowels; or she must renounce her character for knowledge and policy, and perhaps with it, her existence, as a commercial city.” In the year 1811, one of the most acute and learned works[[193]] that has graced the literary annals of our country, appeared from the pen of Dr. Bancroft, in order to prove that the yellow fever is no other than an aggravated form of that multifarious disease, which is well known to result from the action of those exhalations commonly denominated marsh miasmata, and that, like all fevers from that cause, it possesses no contagious quality; but he adds, “it is indeed probable that the miasmata of particular towns, mostly either sea-ports, or accessible to shipping, in which the aggravated forms of yellow fever have almost exclusively prevailed in the West Indies, the United States of America, and the Southern parts of Europe, differ from the common exhalations of marshes, in quality, as well as degrees of concentration: but whether this difference be occasioned merely by the greater heat which, at such times, commonly exists in these towns than in the surrounding country, and which may exalt the powers of such miasmata, by perfecting the decompositions which produce them, or whether it be partly the result of a difference in the organized matters decomposed by that excessive temperature, I am unable to determine.” We must refer the reader to Dr. Bancroft’s[[194]] work for farther information upon the subject; and we have little doubt but that, after an attentive consideration of the rich store of facts and observations which this author has presented to us, he will be led to a conclusion in favour of the general non-contagious nature of this malady, although we by no means intend to deny that it never assumes the character of a contagious Epidemic. Sir Gilbert Blane, whose testimony upon this subject must necessarily have great weight, has made the following observations. “In that district of the globe in which are situated the islands called the Great and Little Antilles, also in the continental regions round the gulph of Mexico, and along the coast of South America, the fevers which prevail there have certain symptoms peculiar to themselves, and not occurring in any other part of the globe, except when carried from thence, which they sometimes have been, particularly to the sea-port towns of North America, and the South of Europe.
The peculiarities alluded to, consist in a universal yellowness of the skin, and the vomiting of a dark coloured fluid, resembling the grounds of coffee.
Sir Gilbert Blane considers, that the yellow fever may proceed from three remote causes, very distinct in their nature. The First, is that which consists in the exhalations of the soil, such as produce the endemic fevers in other countries and climates, and prevailing chiefly in autumn. The Second, is that which consists in foul air engendered on board of ships on long voyages, in circumstances of personal filth, and want of ventilation, frequently combined with hardships and privations, and is the same with those stagnated and corrupted effluvia of the living human body, which produce typhus fever. The Third cause is that in which there is no suspicion of foul air, either from the soil, or from the living human body, but merely from circumstances of intemperance, fatigue, and insolation, affecting chiefly, and almost exclusively, new comers from temperate and cold climates.[[195]] The first of these, he says, may be distinguished by the appellation of the Endemic; the second, by that of the Pestilential, Malignant, or Typhus Icterodes; the third, by that of Sporadic.[[196]] And Sir Gilbert adds, that it has been for want of making this distinction, and from classing all these three under one head, that the endless and acrimonious controversies regarding contagion have arisen. There is not the least suspicion in any rational mind, that the endemic and sporadic species are contagious, this is only alleged with regard to the pestilential or typhus species; but it may be asked what proof there is that this last is specifically different from the other two? To this Sir Gilbert answers, that it is a matter of history; that besides the endemic and sporadic fevers prevailing at all times in the above-mentioned regions, there has occurred at various intervals of time, a raging epidemic,[[197]] which could be traced to the arrival of a ship or ships in the circumstances above recited, and at a season in which the ordinary malignant fevers do not prevail. To those engaged in researches upon this obscure subject we would farther recommend the perusal of a work lately published by that veteran in the cause, Dr. Jackson, on the subject of the Andalusian Fevers[[198]]; in which he examines the evidence in support of the supposed introduction of the yellow fever into Spain, and of its real or supposed propagation by contagion. The importation of the disease from a foreign country is credited by the authorities and mass of people in Spain, though the author thinks it has never been proved by evidence, or even brought to reasonable probability; the events of the year 1820 stripping the assumption of every claim to credence, as no attempt has been made to trace the disease, in that instance, to foreign origin. The belief universally obtains through Spain, that the disease is personally contagious; that is, capable of propagation from individual to individual, by contact or proximity; Dr. Jackson, however, considers that this opinion, confidently as it is maintained, is invalidated by authentic facts and records; but we must proceed to the consideration of our second problem, viz: