WHILE ITS PROXIMATE CAUSE IS PLAIN. 821 



product capable of being subjected to chemical 

 analysis. And it will be seen hereafter, that all 

 the mephitic gases diminish the process of respi- 

 ration, reduce the temperature of the body, and 

 thus tend to produce a chill, by which nearly all 

 diseases are ushered in, in short, that their in- 

 fluence is to vitiate the nutritive properties of the 

 blood, and diminish all the energies of life. 



But although we may not know precisely 

 whether malaria depends chiefly on the agency 

 of carbonic acid and vicissitudes of temperature, 

 or some other yet undiscovered effluvia, in con- 

 junction with heat, cold, and moisture, we can 

 clearly distinguish the manner in which they 

 operate, and the effects they produce on respira- 

 tion, sanguification, secretion, nutrition, and all 

 the vital functions. Whether generated in large 

 cities, confined dwellings, or marshy districts, its 

 morbid influence is essentially the same, modi- 

 fied, however, in all cases, by climate and season, 

 being always more concentrated and malignant 

 where the temperature is highest, ceteris paribus. 

 And whether cholera be contagious or not, like 

 typhus, yellow fever, and plague, it is generated 

 by foul air, bad diet, filth, cold, moisture, fatigue, 

 and the depressing passions, where none of them 

 before existed. 



In the large towns of Great Britain, typhus 

 fever is sometimes more fatal during winter than 

 summer, because the want of sufficient clothing 



