8 
The Bulletin 
toplasm. One important function of the salts in the blood is to main¬ 
tain the vitality of the tissues. This is one of the principal functions 
of sodium chloride. 
The excess of mineral bases in the food must be maintained at a 
high level. 
Fate of Additional Minerals Given in Feed 
Hunt 9 of the Laboratory of Experimental Pharmacology and Ther¬ 
apeutics of the Harvard Medical School gives the following as his 
opinion of the fate of some of the salts added to feed mixtures: “It 
is my impression that only a small amount of the calcium and magne¬ 
sium, in the formula you propose, would be absorbed; that the potassium 
chloride would be completely and quickly absorbed and, unless the 
body needed it, would be equally quickly excreted by the kidneys. 
At least some sodium sulphate is absorbed; probably much of it if 
the quantity is small. The sodium of the NaOH would certainly be 
absorbed.” 
Wells * 1 °, Director of Medical Research of the University of Chicago, 
gives the following as his opinion: “The character of the compounds 
that will form in a mixture such as you describe will depend entirely 
upon the concentration of the different ingredients. In the case of the 
carbonates with volatile anions you would naturally get complete sub¬ 
stitution by the chlorine or lactic acid radical and therefore have a 
mixture of sodium lactate and sodium chloride or the corresponding 
calcium salts, in the presence of sour milk. With the sodium sulphate 
and potassium sulphate the amount of formation of sodium chloride 
or sodium lactate will be entirely a proposition of mass action and the 
sulphates and chlorides will predominate. In any case, all the com¬ 
pounds that would be formed would be entirely absorbed. It is always 
hard to estimate how much calcium salts is absorbed because a con¬ 
siderable portion of this is always secreted back into the intestines 
and no matter how much is given by the mouth of any calcium salt but 
a small amount passes out in the urine and can be found circulating 
in the blood at any one time.” 
The salts are of no value from an energy standpoint. Their changes 
are not accompanied by the liberation of heat energy, or if so, this is 
so small that it has never been measured 1 b They do, however, main¬ 
tain a normal composition and osmotic pressure. They play an import¬ 
ant part in controlling the flow of water to and from the tissues. They 
constitute the essential part of living tissues, and are essential to its 
normal reactions. 
9 Private correspondence. 
1 °Private correspondence. 
“Smith, F. A., Manual of Veterinary Physiology. Third edition. 
