310 WILEY— INFLUENCE OF PRESERVATIVES [April 25, 



a certain mineral hunger. In other words, mineral substances play 

 a double role in animal and plant nutrition : First, they may serve 

 as real foods, necessary to the formation and nutrition of the tissue. 

 In the animal economy this is especially true of phosphoric acid 

 and lime. In the second place, they are necessary to the func- 

 tional activity of the various organs of the body, irrespective of any 

 part they may take in direct nutrition. 



The necessity of saline solutions in the blood is known to every 

 physician and physiologist. If the blood were deprived of all of its 

 saline constituents the circulation would be impeded, restricted, or 

 stopped, and death would result. In cases of collapse in disease 

 saline injections in the blood are often used as a restorative measure. 

 These salts in solution stimulate the heart's action and undoubtedly 

 are active in the osmotic operations of the cells. This is one of the 

 facts which show the intimate relation existing between physical 

 chemistry and physiology. 



Common salt is the most frequent and most abundant of the 

 saline constituents of the blood, but the alkalinity of the blood is not 

 due of course to the common salt, which is a neutral substance. 

 The existence of alkaline carbonates or other alkaline salts is neces- 

 sary to the vital functions. Whi^e it is true that the digestion in the 

 stomach takes place in an acid solution, it is likewise true that any 

 excessive acid must be neutralized and enough of alkali added in the 

 small intestine in order that the further digestion of the food may 

 properly take place. That saline bodies other than common salt or 

 the alkaline carbonates may be useful, however, in the perform- 

 ance of the vital functions cannot be denied, though it might be 

 difficult to demonstrate their absolute necessity. Hence the intro- 

 duction of saline bodies, which may or may not be of an antiseptic 

 character, may, within certain limits, have a favorable influence upon 

 health and digestion. At the same time it should not be forgotten 

 that all excess of such bodies imposes upon the excretory organs an 

 additional burden, which, while it might not impair their efficiency 

 even for a number of years, might finally produce a condition of 

 exhaustion which would be followed by serious consequences. 

 Especially is this remark true of the kidneys, which appear to be a 



