REPAIR AND WASTE 299 



oxygen. In fact, as before stated, the agency of the oxygen 

 is concerned in the general metamorphosis of the tissues. 

 In this process we at once find an evolution of heat and 

 energy, which is the result of this phenomenon. 



Heat is disseminated with more or less rapidity through 

 all bodies, varying according to their density, but in 

 general more easily penetrating those that are solid than 

 those that are porous. Thus, the amount of heat is never 

 constant, but is continually passing and repassing through 

 matter, seeking an equilibrium or level. The human body 

 is also subject to the same law; and as heat is constantly 

 being generated in its tissues, it must also as constantly 

 be eliminated ; and vice versa, for the very reason that it is 

 thus perpetually being removed, it must be continually 

 generated. Thus, since the exercise of the day has dimin- 

 ished the force or quantity of the living power, the neces- 

 sity arises for rest to restore it during the night. During 

 sleep the functions are performed in a slower and more 

 feeble manner, or cease entirely; animal heat is less rapidly 

 evolved; the living power accumulates; the organs re- 

 cover their tone, and the whole vital energies are con- 

 centrated, ready to meet the exigencies of the coming 

 day. 



PERSPIRATION 



In a previous chapter we have already discussed the 

 effects of any check to the perspiratory functions. Never- 

 theless, in order to make the subject more clear, we will 

 consider it again in detail, although in doing so some repe- 

 titions will necessarily occur. 



The perspiratory excretion exerts an important influ- 

 ence on the integrity of the living organism. A sudden 

 check or prolonged retention of it in the body is certain to 

 produce more or less serious derangement of the functions. 

 There is no disease, perhaps, in which the perspiratory 

 function is not in some measure affected. 



