80 VERTEBRATED ANIMALS. 



gentlemen touched any part near the seat of life, as the 

 tongue or side, it felt nearly as cold as a piece of ice 

 under ordinary circumstances. Thus though these per- 

 sons were in a temperature of 260, and even in some 

 experiments as high as 264, the heat of their bodies 

 never rose higher than 102, making a difference of 

 160, between them and the air in which they were 

 placed. 



In what manner the heat is carried off. If we look 

 for the means which nature displays to carry away the 

 superabundant heat to which the system is exposed, we 

 shall find that perspiration is the most obvious, though not 

 the only one to which we can refer. The boiling water, 

 in the rooms in which these experiments were made, as 

 is the case every where at the surface of the earth, nev- 

 er exceeded 212 degrees, the remaining heat being car- 

 ried off by the steam rising from its surface. In like 

 manner the gentlemen state, that within a few moments 

 after entering the heated room, their persons were cov- 

 ered with a profuse perspiration, which continued as 

 long as they staid. But besides this cause, the operation 

 of heated air on the system is not so great as might be 

 expected in consequence of its being so highly ratified, 

 and expanded, that comparatively few particles come in 

 contact with the surface of the body. It has been found 

 also, that the quantity of oxygen consumed by the lungs, 

 (which is the source of animal heat,) during these experi- 

 ments, is much less than ordinary, most probably owing 

 to the rarity of the air. 



It appears that these are the several causes which 

 conspire to keep the temperature of the animal system 

 nearly the same as ordinary, when exposed to high de- 

 grees of heat. 



STRUCTURE OF THE BONY, OR OSSEOUS FABRIC. 



The framework of all vertebrated animals is made of 

 bone, the appearance of which we need not describe. 



What are the means employed by nature to resist high degrees of heat 1 

 Why is the temperature of boiling water stationary at 212 1 



