iti rotation to Dii^aki. Sl'^ 



ance of these circumstances, as determining the endemic disorders 

 and average health of different localities, exclusively even of 

 the habits and employment of the people in each. Every coun- 

 try and district furnishes such instances ; and all concur in 

 proving that we must estimate the influence of temperature 

 upon the body, and especially of heat, subordinately in great 

 part to these more varied conditiohs. Isothermal zones would 

 afford a very uncertain measure of the character or prevalence 

 of disease.* 



But it is a further question here, whether variations of at- 

 mospheric temperature may not induce a state of body, render- 

 ing it more liable to teceive specified infections, however ge- 

 nerated by agents without ? That there are such differences 

 of bodily condition, however vaguely known to us by external 

 signs, must be admitted. And it is perhaps not a rash infer- 

 ence from the temporary effect of exposure to great heat, in 

 quickening the circulation and augmenting the animal tem- 

 perature, that continued exposure to the same cause, even 

 much less in degree, may keep the constitution in a state prdttfe 

 to morbid actions, when the exciting causes are present. The 

 uncertainty in this case depends in part on our ignorance of the 

 equality of the causes, and of the relative degree of exposure 

 to them ; and can only be met by strong presumption, or actual 

 observation of change in the bodily state. But I think it im- 

 probable, seeing especially the small increase of animal tem- 

 perature from elevation of that without, that heat alone is con- 

 cerned in producing such alterations : and, if depending on at- 

 mospheric causes, it is likely that these are of mixed kindi 

 and blended with other actions more peculiar to the body it* 

 self.t 



* Many excellent papers on this subject have appeared of late in the 

 Transactions of our provincial Medical Associations, based on that statisti- 

 cal method which alone is capable of affording sound results. They all shew 

 the intirtiate relation between the nature of the surface and the prevalence 

 or infrequency of particular diseases in given localities ; a point in which 

 external temperature is only indirectly concerned, but where the effects arc 

 of singular importance in a practical view. Long and careful averages can 

 alone be effectual in expounding them, by removing gradually all extrinsic 

 or accidental circumstances. 



t Thfe best observations we possess, shew that the change of temperature 

 in the human, body, made by extremes of natural climate, does not exceed 



