PESTILENCE is a general term applied to those diseases of an epi demic character which affect large masses of a population, and are remarkable for their destruction of human life. The two forms of disease to which this term is most frequently applied, are plague and Asiatic cholera.
Plague is a disease of so fatal and malignant a nature, that to this very it probably owes its nomenclature. The nosological definition of this disease by Dr. Cullen is perhaps as correct as can be given in few words :—" A typhus fever, in the highest degree contagious, and accompanied with extreme debility. On an uncertain day of the disea.e, there is an eruption of buboes or carbuncles." Dr. Patrick Russell, who practised at Aleppo during the plague of 1760-1-2, informs us that its progress at its commencement is much the same in the several parts of the Levant as in the cities of Europe. It advances slowly, fluctuating perhaps for two or three weeks; and although at that period it generally proves fatal, yet it is often unattended by its characteristic eruptions. Indeed the cases in which the eruption is wanting constitute the most rapidly fatal type of the disease. The general derangement of the system which ushers in an attack of the plague, is much like that which commences the course of ordinary fever. A sense of Bold, with some shivering, which is soon followed by heat and acceleration of the pulse, with giddiness, headache, depres sion of strength and spirits, white tongue, vomiting or diarrhoea, and great oppression about the prucordia, are among the first symptoms of the disease. These are succeeded by a burning pain about the pit of the stomach ; by a peculiar muddiness of the eyes; by coma, delirium, and other affections of the sensorium, which terminate by death in some cases on the second or third day, before the pathognomic sym ptoms, buboes and carbuncles, have appeared. In other cases these last mentioned symptoms are present, together with purple slots and ecchymoses, which belong to the plague in common with other malignant fevers. Though these are the ordinary symptoms of plague, they are not invariably observed in the same individual ; but many varieties occur, which chiefly have reference to the greater or less virulence of the disease, and the absence or presence of some particular symptoms. Thus, we are informed by Sydenham that in the infancy of the great plague of London scarce a day passed but some of those who were seized with it died suddenly in the streets, without having had any previous sickness; the purple spots, which denote immediate death, coming out all over the body, even when persons were abroad about their business ; whereas after it had continued for some time, it destroyed none, unless a fever and other symptoms had preceded.
Dr. Russell describes six classes or varieties of plague, in some of which the fever appears to have been very violent, while in others it was proportionally mild. The most destructive forms of the disease, according to this author, were marked by severe febrile symptoms; and the infected of this class seldom or never had buboes or carbuncles. The bubo however was the most frequent concomitant afterwards ; carbuncles, on the contrary, were remarked in one-third of the infected only, and were seldom observed at Aleppo earlier than the month of May, rims three months after the disease began to spread. The car buncle increased in the summer, was less common in the autumn, and very rarely was observed in the winter. The absence of bubo and carbuncle at the commencement of the plague has been one of the grounds of contention among writers as to tho real nature of the disease. Diemerbroech and some others assure us that no one symptom is pathognomonic of plague, and Dr. Russell concludes that "the plague, under a form of all others the most destructive, exists without its characteristic symptoms, can admit of no doubt." From all the evidence upon this subject that we have been able to collect, it plainly appears that authors are by no means agreed on the existence of the plague as a distinct disease. The symptoms, morbid changes, history, and mode of propagation of plague, bear so close a resemblance to those of the malignant typhus of this country, that it is difficult to regard them otherwise than as types of the same disease. This opinion is strengthened by the authority of Dr. Mackenzie, who resided thirty years at Constantinople. "The annual pestilential fever of that place,' he observes, " very much resembles that of our gaols and crowded hospitals, and is only called plague when attended with buboes and carbuncles." Sir John Pringle too observes, " that though the hospital or gaol fever may differ in species from the true plague, yet it may be accounted of the same genus, as it seems to proceed from a like cause, and is attended with similar symptoms." The buboes which charac terise plague consist of inflammatory swellings of the glands in the groin and armpits ; the parotid, maxillary, and cervical glands some times, but less frequently, become affected. These buboes may either suppurate or gradually disperse : when suppuration occurs, it is seldom till the fever has begun to abate, and is manifestly on the decline, as about the eighth or ninth day. Carbuncles consist of inflamed pustules, or angry pimples, which, instead of suppurating, frequently terminate in mortification. They may be seated on any part of the body.