54 
Append a, 393 
That the contagion of the plague, supposing it to be present in the. 
state of fomites,* might.be rendered innoxious by a temperature be- 
low that of boiling water, appeared to me not improbable, from the 
evidence of a fact recorded by various writers; viz. that the plague, 
in countries where it prevails, ceases as soon as the weather becomes 
very hot. “Extreme heat,” says Dr. Russell in his Natural History 
of Aleppo, (vol. ii, p. 339,)p‘seems to check the progress of the dis- 
temper; for though the contagion and the mortality increased during 
the first heats in the beginning of the summer, a few days continu- 
ance of the hot weather diminished the number of new infections. 
July is a hotter month than June; and the season, wherein the plague 
always ceases at Aleppo, is that in which the heats are most excess- 
ive.” In another part (p. 284) of the same volume, Dr. Russell 
states the greatest heat at Aleppo in June to have been 96° of Fah- 
renheit, and that of July 101°, in the shade. 
_ Arguments, also, derived from chemical reasoning, appeared to me 
to strengthen the probability that a temperature, raised to no great ex-- 
tent, would suffice for the decomposition of infections or contagious 
matter.+ Of the nature of contagion we are, it is true, entirely igno-_ 
rant. But we are entitled to conclude that it is in no case identical 
with any one of the simple or compound gases, with which chemistry 
has made us acquainted, and which are unchanged by a temperature 
below 212°; because each of those gases has been breathed, many 
of them very frequently, without exciting a specific disease. The 
subtile poisons which propagate contagious distempers, being the pro- 
ducts of organic life and of morbid conditions of the animal body, 
are, it is probable, of a complex pature, and owe their existence to 
aflinities which are nicely balanced and easily disturbed ; even more 
easily than those maintaining some of the products of vegetable life, 
which lose their original properties, and acquire new ones, when ex- 
posed to temperatures of no great amount. Thus, starch is convert- 
BS ira eee eee i 
% 
expresses contagious or infectious matter 
* Fomites (the plural of fomes, fuel) ' 
: 2 h as wool, elothing, &c. In this state of con- 
existing in absorbent substances, suc , 
finement, it seems to acquire increased yirulence and activity. 
+ Luse the terms ‘infection’ and ‘contagion’ as synonymous, because no sufficient 
It would be unseasonable to enter, 
verbal part of the subject, will find an exce 
son, Dr. Charles Henry) in the Dictionnaire 
p. 549. Paris: 1822. 
Vot: XXI.—No. 1. 50 
de Médecine, art. Contagion, vol. v, 
