upon Animal Bodies'. 13 



support of animals. The great and striking analogy be- 

 tween the animal and vegetable kingdoms consists in 

 the power of evolving caloric, or, in other words, re- 

 sisting, while alive, the temperature of the surrounding 

 medium. It has been ascertained by some late experi- 

 ments in France, that the plant spadix will raise the 

 thermometer 15|°, while the parts concerned in fructi- 

 fication are developing. Man, though classed among 

 the hot-blooded animals, is among the lowest of the 

 class ; the thermometer usually pointing, when placed 

 on the central parts of the body, at 97° Fahrenheit. The 

 atmosphere combines with, and becomes the recipient 

 of, the caloric, carbon, and hydrogen, which are evolved 

 from the blood during its circulation through the lungs, 

 the retention of which principles would become the 

 fruitful source of disease. 



The lungs may justly be regarded as the mediate 

 source or cause of those superior degrees of heat ob- 

 servable in all animals possessing this organ, not because, 

 as many modern philosophers believe, all animal heat is 

 derived from the decomposition of the oxygenous por- 

 tion of the air, but because respiration is essential to 

 the exercise of every other function concerned in main- 

 taining those actions which generate animal heat. Great 

 diminution of temperature in animals, like frost in vege- 

 tables, may cause a suspension in the exercise of their 

 functions, even to an extended period. 



The ground on which Black, Crawford, Lavoisier, and 

 others, have constructed their theories concerning: the 

 generation of animal heat by the pulmonary absorption 



