DYNAMIC EQUILIBRIUM 257 



No matter what organ or tissue it is that fails to function 

 normally it must remain in dynamic equilibrium with the blood, 

 and through the blood with every other tissue and organ in the 

 body. Every change occurring anywhere in the body sets in 

 motion a series of far-reaching alterations tending to restore 

 equilibrium. It is this constant adjustment of physical and 

 chemical force and matter brought about mainly via the inland 

 transport system that goes to make up the metabolism of the 



organism. 



Other materials are carried by the plasma, viz. : 



I. SUBSTANCES TO BE USED BY THE TISSUES. 



AmTmTAcids I. From alimentary canal and from 



Accessory substances and Salts I storehouses 



Hormones From thoracic duct and from depots. 



II. SUBSTANCES EXCRETED BY THE TISSUES. 



Urea \ 



Ammonia ' ,. . 



Creatin and Creatinin f Eliminated by the kidneys (q.v.). 



Purins - ) 



B.B. 17 



