SALTS. 



101 



into combination with the various tissues, and also probably in 

 aiding the chemical changes of parts of which they do not form a 

 normal constituent. They help to render certain substances sol- 

 uble, and stimulate the cells of certain glands to more active 

 secretion, e.g., the kidney excretes more urea when there is an 

 abundant supply of common salt in the food. 



