250 ANIMAL HEAT. 



lution of heat is most evident during flowering and the 

 germination of seeds, the times at which the largest 

 amount of carbonic acid is exhaled. 



The quantity and quality of food consumed by man and 

 animals in the different climates and seasons, also appear 

 to be adapted to the production of various amounts of 

 heat by the combination of carbon and hydrogen with 

 oxygen. In northern regions, for example, and in the 

 colder seasons of more southern climes, the quantity of 

 food consumed is (speaking very generally) greater than 

 that consumed by the same men or animals in opposite 

 conditions of climate and seasons. And the food which 

 appears naturally adapted to the inhabitants of the coldest 

 climates, such as the several fatty and oily substances, 

 abounds in carbon and hydrogen, and is fitted to combine 

 with the large quantities of oxygen which, breathing cold 

 dense air, they absorb from their lungs. 



The influence of the nervous system in modifying the pro- 

 duction of heat has been already referred to. The experi- 

 ments and observations which best illustrate it are those 

 showing, first, that when the supply of nervous influence to 

 a part is cut off, the temperature of that part falls below 

 its ordinary degree ; and, secondly, that when death is 

 caused by severe injury to, or removal of the nervous 

 centres, the temperature of the body rapidly falls, even 

 though artificial respiration be performed, the circulation 

 maintained, and to all appearance the ordinary chemical 

 changes of the body be completely effected. It has been 

 repeatedly noticed, that after division of the nerves of a 

 limb, its temperature falls ; and this diminution of heat 

 has been remarked still more plainly in limbs deprived of 

 nervous influence by paralysis. For example, Mr. Earle 

 found the temperature of the hand of a paralysed arm to 

 be 70, while the hand of the sound side had a tempera- 

 ture of 92 F. On electrifying the paralysed limb, the 

 temperature rose to 77. In another case, the temperature 



