FORBES: MINERAL ELEMENTS IN NUTRITION 443 



These results are not considered to controvert evidence as to 

 specific therapeutic effects of these phosphorus compounds in 

 relations other than those considered in this study. 



Even granting the debated superior nutritive value of organic 

 or inorganic compounds of phosphorus, however, it is undoubted- 

 ly a fact that the organic phosphorus content of the animal body 

 is a very small part of the total phosphorus, and as certainly 

 true that a very much larger proportion of organic to inorganic 

 phosphorus prevails in the diet of all omnivora and herbivora 

 than in the bodies of these animals; and as for carnivora, the 

 consumption of flesh and bones together would give them ap- 

 proximately the same proportion of organic to inorganic phos- 

 phorus in the diet as in their own bodies. It would seem, there- 

 fore, that for purposes of growth, the usual diet of animals must 

 contain a sufficiently large proportion of organic to inorganic 

 phosphorus. In this relation, then, the important considera- 

 tion is simply one of the total phosphorus of the ration, and 

 any such supplemental phosphorus as is to be added to the diet 

 of the healthy, growing animal may be added as inorganic 

 phosphate. 



The amount of phosphorus which an animal will tolerate, 

 when added to the ration in readily soluble form, is definitely 

 limited at an amount much less than will be acceptable in its 

 natural relationships in foods. 



It seems unlikely that, with grown or growing animals, any 

 ration composed from natural foods, and supplying the nitro- 

 gen requirement, will fail to furnish enough total phosphorus 

 to maintain phosphorus equilibrium. That many such rations 

 are lacking in the amount of phosphorus essential to maximum 

 retention and growth, however, is as certainly true. 



The results of our experiments indicate that the possibility 

 of influencing, to a practical extent, the relative development of 

 tissues and organs of livestock by the addition of isolated com- 

 pounds of phosphorus to the ration is probably limited to the 

 density and strength of the bones; but this is not saying that we 

 may not be able by the use of these same compounds profoundly 

 to influence physiological functions. 



