Contention on such a subject as contagion is not to be wondered at, when we consider the obscurity attendant on all that relates to subtle agencies (the supposed qualities of contagion); and inasmuch as we observe that different effects arise from the same causes, as also similar effects from different causes in the human body, a vast field is necessarily opened up for contention, as every impartial observer will admit.
That the doctrine of contagion is of comparatively modern origin (subsequently to Hippocrates), historical research fully shows, and it would be really an endless, if not an unprofitable, task to review the innumerable arguments of which contagionists and their opponents have from time to time availed themselves in support of their respective opinions, especially when the controversialists can enlist on the one side such names as Chisholm, Clark, Cleghorn, Pringle, Bianchi, Lind, Meade, Warren, and a host of others, as contagionists, and on the other side, as non-contagionists, such men as Hillary, Huck, Hunter, Jackson, Bouland, Pinckard, Bancroft, Scott, Rush, Miller, Caldwell, Chervin, besides very many others of more modern date.
With reference to our present subject, contagion, it has always been with me a difficulty to understand the precise or real sense in which contagionists generally write; and I must confess my inability to comprehend the meaning they attach to the term contagion, and also to that of infection, so contradictory are their applications of the terms contagion and infection, some using them synonymously, others making distinctions, between contagion and infection, of such arbitrary signification, that they are really neither definite nor intelligible; whilst contagionists themselves often depart from their avowed principles. For example, Papôn, in his work entitled ‘Epoques Mémorables de la Peste,’ considers the undoubted causes of plague to be uncultivated lands, marshy soil, corrupt lakes, filthy cities, concurring with occasional causes, such as intemperature of the seasons and famine, whilst the bent of his researches is evidently to prove that in every modern plague foreign contagion was the cause!
Dr. Meade, notwithstanding his advocacy of contagion, like most other contagionists, is guilty of inconsistency in stating, “that a corrupt state of the air attends all plagues.”
Again, Dr. Patrick Russell, a great contagionist, when giving a most minute account of the origin, spread, and decline of the plague, admits the inutility of quarantine laws for the prevention of contagion, and, curiously enough, he lays much stress on what he terms “a pestilential constitution of the air.”
Dr. Hamilton, another great contagionist, affirmed that the influenza which prevailed in England,—in fact, all over Europe, in the year 1782, was contagious, and that the malady was propagated by contagion only; yet at the same time he informs us that, “in different places, many hundreds were seized with pestilence at one and the same time:” and Dr. (afterwards Sir Gilbert) Blane, also a contagionist, speaks of the influenza as having affected mariners in the very midst of the ocean!
It would appear, however, that to reconcile conflicting opinions, various modern writers of experience and talent have endeavoured to show that epidemic diseases, not contagious at their commencement, may acquire that character from confined air, filth, and other accumulations. That impure air, want of light, crowding together unwashed numbers, &c., will by predisposition contribute to the production and aggravation of disease, as we observe to be the case in jails, hospitals, and in camp, I can fully understand; but that epidemic diseases, such, for instance, as plague, yellow fever, or cholera, are ever propagated by contact—contagion, I, after twenty-five years’ residence in pestilential countries, have no reason to believe; for I have seen epidemics seize on vast numbers at once,—I have sometimes seen them attack a whole people, or a part thereof, whilst at other times they have prevailed amongst the inhabitants of particular provinces and cities only. On what principle of contagion or infection, I would ask, can such universality or partiality of disease be accounted for or explained? Surely not from any cognizable property of contagion. All that I have ever read and seen of the nature of epidemics militates against the doctrine of contagion, whilst all that has been adduced, as far as my researches show, in support of contagion, has been of a negative, or at all events not of a positive, nature.
Epidemic diseases, which have appeared and spread at different seasons,—in fact, at all times of the year,—in the middle of summer, for instance, as well as in the depth of winter,—which have also been found traversing whole continents, continuing their course for many successive months, and often assuming a definite direction or progress, often affecting large masses of people living on the same spot, while others in adjoining localities are exempt,—cannot, I contend, be attributed to contagion, but to the qualities and influences of the surrounding atmosphere, coupled with enervating habits, &c.
Again, contagious diseases are recognizable by the determinate periods of their phenomena, especially as regards specification, as also by their mode of propagation, whilst, if epidemic pestilences were dependent on, or caused by, contagion, they would never cease until whole communities became extinct!
A period of one hundred and sixty years has elapsed (up to the year 1832) since the occurrence of any plague or aggravated pestilence in this our own country, notwithstanding our intercourse with countries where awful pestilence may be said always to exist. Whence, then, I would ask, our immunity for so long a period, if pestilence BE IMPORTABLE AND CONTAGIOUS? for it would appear that in spite of our increased intercourse and commerce with pest-ridden spots, our freedom from pestilence has been greater, manifestly from the change in our moral and physical condition since the seventeenth century, which has given rise to a degree of public health to which our ancestors were strangers when pestilence was rife in our land, and which is not attributable, as some may suppose, to the vigilant enforcement of those bugbears, ‘quarantine laws,’ of which a recent writer very justly observes, “that they are not only absurd and needlessly burthensome to commerce, but perverse and barbarous in the extreme, independent of the injurious fears induced, being as dangerous to communities as they militate against common sense and HUMANITY.”
Whilst on the subject of quarantine, the question may be asked,—How is it that so little has been elicited in support of contagion from the working of lazarettos?—it being to the interest of those who hold such views to publish THE LETHAL effects of their lazaretto occupations. Might we not expect, from the testimony of the responsible officers in charge of such establishments, to be informed of an awful annual sacrifice of life in such perilous occupations, from the terrible exposure of those employed in them in unpacking contagion, as it were wholesale? Have we any evidence from lazarettos to warrant the belief in contagion? I think not; at least my not very limited researches have afforded me no such evidence, and I fear that it is with the subject of contagion, as with other matters appertaining to pestilence, that authors seek for the peculiar facts which especially favour their preconceived opinions, whilst they strain the simple bearing of facts to answer their own hypotheses. Further, we find pestilence still as prevalent and destructive as in former years in those cities in which the march of improvement has not appeared. Thus Grand Cairo and Constantinople to this day are never free from the plague. Grand Cairo is always crowded by a vast number of inhabitants of the lowest order in the most abject state of poverty. The streets are very narrow and close, and thirty or forty persons often inhabit one small house. It is situated in a sandy plain at the foot of a mountain, which, by excluding the winds, makes the heat more stifling. Through the midst of it passes a great canal, which is filled with water at the periodical overflowing of the Nile, and after the river has fallen it is gradually dried up; into this are thrown all manner of filth, carrion, &c., so that the stench which arises from this and the mud together is insufferably offensive. At certain periods of the year the plague preys upon the inhabitants, first appearing amongst the lowest orders of the people, who are mostly in a wretched condition: its progress is stopped only when the Nile, by overflowing, washes away this load of filth; the cold winds, which set in at the same time, purifying the air. The plague in Constantinople is generally observed to break out in that part of the city which is low and marshy.
On searching the ancient records of medicine, and on referring to history, both sacred and profane, nothing in the shape of evidence can be found, previously to the time of Hippocrates, to show that epidemic pestilences were thought to be contagious; in fact, all writers before the Arabians invariably speak of epidemic diseases as arising from places, seasons, and constitutions of the air; and nowhere in his works does the great parent of medicine, the erudite and all-observant Hippocrates, entertain the idea of contagion:—Δεῖ δὲ καταμανθάνειν τὴν Κατάστασιν τῶν ‘Ωρέων ἀκριβῶς, καὶ τῶν Νούσων ἑκάστην.
I would ask of all unprejudiced persons, What could contagion have had to do with the terrific and wide-spreading outbreak of pestilence at Kurrachee (see ‘History of Pestilences,’ p. 177), where 8000 victims were at once seized and carried off in a few days?
But that which I would urge in support of the NON-CONTAGIOUSNESS of epidemic pestilences, irrespective of EVERY other authority, is the remarkable fact, that in our most ancient medical treatise, the 13th chapter of Leviticus, no mention whatever is made of epidemic diseases being reckoned contagious, although at the time when the Levitical code was being propounded there was no lack of experience in epidemic diseases; for in the days of Moses the times in Egypt were calamitous indeed:—pestilence and famine ran riot through the land. Had epidemic diseases, then so common and lethal in Egypt, been considered contagious, the presumption is that they would have been enumerated as such among those which were specified as possessing that character, viz. leprosy, scabies, lues, &c.; and when we observe such minuteness displayed in the Mosaic ordinances, to the very freeing of houses from damp previously to occupation, we cannot suppose that precautionary directions, as regards such universal and lethal maladies as epidemics, would have been omitted. With this remarkable fact before us, derived from sacred authority, I feel at a loss to conjecture the grounds on which the idea of contagion is at all entertained, more especially as we have the occurrence of pestilential disease not only foretold, but their very nature and mode of production positively conveyed to us from the same divine source.
“The Lord shall smite thee with a consumption, and with a fever, and with an inflammation, and with an extreme burning,” &c. (Deut. chap, xxviii.)—“And it shall become small dust in all the land of Egypt, and shall be a boil breaking forth with blains upon man, and upon beast, throughout all the land of Egypt.” (Exod. chap, ix.)—“But the hand of the Lord was heavy upon them of Ashdod, and he destroyed them, and smote them with emerods” (violent dysentery), “even Ashdod and the coasts thereof.” (1 Sam. chap, v.)—“I also will do this unto you; I will even appoint over you terror, consumption, and the burning ague,” &c. (Levit. chap. xxvi.)—“I will smite the inhabitants of this city, both man and beast: they shall die of a great pestilence.” (Jeremiah, chap. xxi.)—The sun and the moon standing still in their habitations, the mountains trembling, the waters overflowing, causing famine and pestilence. (Habakkuk, chap. iii.)—“Behold, I will send a blast upon him.” (2 Kings xix.)—“The Lord shall make the rain of thy land powder and dust.” (Deut. xxviii.)—“Thy heaven shall be brass, and the earth iron.” (Ibid.)—“And if the family of Egypt go not up, and come not, that have no rain, there shall be the plague,” &c. (Zechariah, chap. xiv.)
In conclusion: fully impressed with the necessity that for the purpose of insuring anything like rational conclusions as to the nature and origin, or causes, of epidemic pestilences, we should not only enter upon their investigation divested of all prejudice in favour of exclusive doctrines, but at the same time be actuated by an impartial desire for COMPREHENSIVNESS, as being the only, the true way to surmount the innumerable difficulties attendant on the investigation of universal distempers, and premising with the opinion that at the onset we should be cognizant of the absolutely necessary distinction between the predisposing and the exciting causes of disease, the due consideration of which guides to preventive or sanitary measures, I take leave to reiterate my opinion,—an opinion founded on a careful review of the foregoing history of epidemics,—that all epidemic pestilences or diseases are to be accounted for on the principle of natural causes, viz., That atmospheric disturbance, consisting of variations of temperature, hygrometric influence, atmospheric pressure, electrical tension &c., are the exciting causes; while, on the other hand, want of light, impure air, especially from defective ventilation, in which are included malaria and all other noxious vapours, from whatever source arising; scanty diet, and habits induced by the irregular, artificial life of many, are the predisposing causes, which by enervating and otherwise spoiling the system, render it more susceptible of external atmospheric impressions in the production of epidemic pestilence or disease.
Λεγέτω μὲν οὖν περὶ αὐτοῦ ὡς ἕκαστος γιγνώσκει, καὶ ἰατρὸς, καὶ ἰδιώτης, ἀφ’ ὅτου εἰκὸς ἦν γενέσθαι αὐτὸ, καὶ τὰς αἰτίας ἅστινας νομίζει τοσαύτης μεταβολῆς ἱκανὰς εἶναι δύναμιν ἐς τὸ μεταστῆσαι σχεῖν. And now I leave every one, whether physician or not, to pass his own opinion concerning it, pointing out whence it was likely to arise, and what causes he thinks sufficient to produce so entire a change in the constitution of the human body.”—(Thucydides on Epidemics.)