23 



lieduction can only be drawn that if the preservative affects the number 

 l)f corpuscles and the amount of hemoglobin at all, it does .so in very 

 Irregular manner, differing in different individuals and in a way which 

 Lan not be used as a basis of any definite conclusion. 



CONCLUSIONS. 



NECESSITY OF MINERAL SUBSTANCES IN THE BLOOD. 



In the consideration of the action of preservatives of a mineral nature, 

 Buch as borax and boric acid, it must be remembered that the animal 

 bs well as the plant possesses 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 forma- 

 tion and nutrition of the tissues. In the second place they are neces- 

 sary to the functional activity of the various organs of the body, irre- 

 spective of any part they may take in direct nutrition. 



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

 sician 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 injec- 

 tions 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 chemist^ 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 common salt, which is a neutral substance. The existence 

 of alkaline carbonates or other alkaline salts is necessary to the vital 

 functions. While 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 performance of the vital functions can 

 not be denied, though it might be difficult to demonstrate their absolute 

 necessity. Hence the introduction 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 con- 

 j dition of exhaustion which would be followed by serious consequences. 

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

 general clearing house for all the surplus of saline matters ingested in 

 the foods. 



