36 Animal Heat. 



materials for warmth under other circumstances. 

 But under active work or movements, albuminous 

 compounds are broken up, and the carbonaceous 

 elements rendered available for the purpose. 



A reference to the table at page 3 1 will explain 

 how this can be permitted. In farther explana- 

 tion it may be stated, that fatty or saccharine 

 compounds are serviceable only for the production 

 of heat as an adjunct to vital force ; but nitrogen- 

 ous compounds are capable, by peculiar action, 

 of becoming not only useful for the manufacture 

 of flesh, but also for the production of the neces- 

 sary animal heat during exercise or work. 



This explains why animals in high condition 

 appear fresh and excited. There is a necessity 

 for movement created in order to consume the 

 highly nutritious material within the body. Wild 

 animals confined to cages are seen to move about 

 incessantly when awake. Here is another mode 

 in which the system endeavours to appropriate 

 the food, and bring about essential vital actions. 

 Were it not thus, disease or death would be an 

 early result, from an accumulation of deleterious 

 principles in the blood, by which it is no longer 

 able to support the body. 



Man and animals consume little food when 

 the body is covered by fat, and exercise but 

 sparingly taken. The muscles are not developed 

 because they are not used, in fact such a body is 

 not capable of much exertion, by reason of that 

 want of muscular development. It is neither so 



