On the spread of the Plague is the following:—"The plague is a real poison, which being bred in the southern parts of the world, maintains itself there by circulating from infected persons to goods, that when the constitution of the air happens to favour infection, it rages with great violence." Contagious matter is lodged in goods of a loose and soft texture, which being packed up, and carried into other countries, let out, when opened, the imprisoned seeds of contagion, and produce the disease whenever the air is disposed to give them force, "otherwise they may be dispersed without any considerable ill effects." Gibbon thus speaks of the above quoted work: "I have read with pleasure Mead's short but elegant Treatise concerning Pestilential Disorders;" many also might read it at the present day with infinite advantage. Mead most satisfactorily combats the opinions of the French physicians who maintained the non-contagiousness of the Plague. Experience proves beyond doubt, that certain conditions of atmosphere, of
which we are ignorant, favour the growth and increase of pestilences as they do of all vegetation.
Dr. Bancroft was of opinion that specific contagions are each and severally creatures of Divine Wisdom, as distinctly and designedly exerted for their production, as it was to create the several species of animals and vegetables around us.
The indigenous fever of Ireland, which has several times shewn itself in an epidemic form, appears to have been as fatal, as the Plague in the South of Europe. Its devastations have generally been associated or preceded by famine and general distress. Dr. Harty, writing in 1820, says that thrice within the last eighty years has the same fever appeared in its epidemic character. In the year 1741 Ireland lost 80,000 of her inhabitants from this cause. It is a maculated typhus, and considered to be a special product of the Emerald Isle. It has been shewn that fever began to exceed its ordinary rate in those places first where famine and want of employment were most severely felt,[[24]] and that in such places and under such circumstances, it was most prevalent and fatal. The physicians generally believed it to have been spontaneously produced and not to have been imported. In the last Famine Fever of Ireland, Liverpool and several other places suffered severely from the
importation of their Channel neighbours with the disease in some instances, and the infection in others about their persons. Hitherto these have to all appearance been the limits of the affection; we know not, however, how soon the time may come when the invisible bonds which have thus chained the disease to certain localities may be severed, and spreading itself like other pestilences in an aggravated form, attack this country as a last and crowning act of retributive justice. At present it has but cost us money and regrets, but if the history of pestilences is to be heeded, there are many tokens which seem to indicate that a few slight concurrent circumstances only are wanting, to bring the full force of this disease upon us; then will there be a sacrifice of life. Edinburgh and other towns of Scotland have had some visitations already, ourselves but slightly, but let our labouring population suffer to any large extent for want of work, and we shall inevitably be the sufferers from that fever which in consequence of general destitution is now always more or less prevalent in Ireland.
The Sweating Sickness prevailed in England alone at first, but at length sought foreign victims. The Cholera is an exotic disease, as well as the Plague, but they occasionally have visited our shores, and their seeds remain among us. The Small Pox is now even not known in some parts of the world, but when once it is established, who can predict the period of its first appearance in an
epidemic form. The history of the disease informs us that in all the countries where it has been introduced, sooner or later an epidemic has seized the inhabitants.
A disease previously unknown in India appeared at Rangoon in the year 1824, which obtained the name of Scarlatina Rheumatica. Four years afterwards it attacked the Southern States of North America, and though the disease was so impartial as scarcely to spare a single individual of any town to which it extended its influence, it was not accompanied with that mortality which has usually been the characteristic of wide spread epidemics.
There is one peculiar feature of all epidemics which may be here mentioned as indicative of some definite, though at present unaccountable cause, operating in the sudden suppression of the disease after a certain period of duration. This distinctive character may almost be considered as a law in reference to these affections; if we take three distinct diseases, the Plague, the Irish Fever and the Cholera, we find the rule apply to all. Of the latter disease we have so recently been witnesses, that I need not quote authorities on this point concerning it. In Dr. Patrick Russell's work on the Plague at Aleppo I find the following remarkable passage. After alluding to the great increase of pestilential effluvia that there must be towards the close of an epidemic, compared with the amount at the onset of the disease, and expressing his
astonishment that so many escape infection, he says: "The fact, however unaccountable, is unquestionably certain; the distemper seems to be extinguished by some cause or causes equally unknown, as those which concurred to render it more or less epidemical in its advance and at its height." He then mentions that in Europe the sudden cessation may be partly attributable to the measures adopted for preventing its extension; but "at Aleppo, where the disease is left to run its natural course, and few or no means of purification are employed, it pursues nearly the same progress in different years; it declines and revives in certain seasons, and at length, without the interference of human aid, ceases entirely."