FEVERS. 541 



rary frequency of the pulse, which cannot be considered as a 

 disease, or, if they do produce a permanent febrile state, it is 

 by the intervention of a topical inflammation, which produces a 

 disease different from what is strictly called fever (VIII.). 



LXXVII. That direct stimulants are the remote causes of 

 fever, seems farther improbable, because the supposition does 

 not account for the phenomena attending the accession of fevers, 

 and because other remote causes can with greater certainty be 

 assigned. 



LXXVIII. As fevers are so generally epidemic, it is prob- 

 able that some matter floating in the atmosphere, and applied 

 to the bodies of men, ought to be considered as the remote 

 cause of fevers : and these matters present in the atmosphere, 

 and thus acting upon men, may be considered either as CONTA- 

 GIONS, that is, effluvia arising directly or originally from the 

 body of a man under a particular disease, and exciting the same 

 kind of disease in the body of the person to whom they are 

 applied ; or MIASMATA, that is, effluvia arising from other sub- 

 stances than the bodies of men, producing a disease in the per- 

 son to whom they are applied. 



LXXIX. Contagions have been supposed to be of great 

 variety; and it is possible this may be the case: but that they 

 truly are so, does not appear clearly from any thing we know at 

 present The genera and species of contagious diseases, of the 

 class of pyrexiae, at present known, are in number not very 

 great. They chiefly belong to the order of fevers, to that of 

 exanthemata, or that of profluvia. Whether there be any be- 

 longing to the order of phlegm asise is doubtful ; and though 

 there should, it will not much increase the number of contagious 

 pyrexiae. Of the contagious exanthemata and profluvia, the 

 number of species is nearly ascertained ; and each of them is so 

 far of a determined nature, that though they have now been 

 observed and distinguished for many ages, and in many different 

 parts of the world, they have been always found to retain the 

 same general character, and to differ only in circumstances that 

 may be imputed to season, climate, and other external causes, 

 or to the peculiar constitutions of the several persons affected. 

 It seems, therefore, probable, that, in each of these species, the 

 contagion is of one specific nature ; and that the number of 



