Studies on Experimental Rickets. 279 



separated by blood vessels, the cartilage exceedingly irregular, the 

 trabecular of the shaft very numerous and surrounded by osteoid. 

 Even the addition to the faulty ration of a large quantity of butter 

 fat did not, therefore, prevent the development of the rickets. 



When, on the other hand, cod liver oil was added to the diet in 

 the proportion of 2 per cent, of the total ration, no pathological 

 condition of any sort developed in the skeleton. The addition of 

 cod liver oil to the faulty diet, therefore, completely prevented the 

 development in the skeleton, not only of changes of a rachitic 

 nature but of all changes of a pathological nature. 



When the faulty diet was still further modified by the sub- 

 traction of the added calcium carbonate, so that calcium was defi- 

 cient as well as the phosphorus and the organic factor, a pathologi- 

 cal condition developed in the skeleton which, however, was not 

 rickets. 



When the calcium carbonate of the faulty diet was replaced by 

 2 per cent. CaHP0 4 , so that the diet was deficient in the organic 

 factor alone, the pathological condition which developed in the 

 skeleton was not rickets but osteoporosis. 



Conclusions: 1. When the content of the diet in the anti-rachitic 

 organic factor or factors is sufficiently low, the protein of the diet 

 and the quantities of Mg, Na, K, CI, Fe and I being optimal or 

 nearly optimal, a disproportion in the quantities of calcium and 

 phosphorus present of such nature that the calcium is in optimal 

 or above the optimal quantity but the phosphorus low, gives rise 

 to rickets. 



2. W 7 hen the level of the phosphorus in the faulty diet is raised, 

 so that both calcium and phosphorus are present in presumably 

 adequate amounts, and the fault in the diet, therefore, becomes 

 limited to a deficiency in the organic factor, a rachitic condition 

 does not develop. A deficiency in the organic factor alone does 

 not produce rickets, as our experiments have attested with other 

 diets. 



3. When no calcium carbonate is added to the diet, so that the 

 quantities of both calcium and phosphorus are low, rachitis dees 

 not develop. 



4. Butter fat is feeble in its anti-rachitic properties. This fact? 

 repeatedly confirmed in our experiments, is in our opinion of 



