Failure of Rats to Develop Rickets. 267 



cold alcohol. The salt mixture was that employed by Osborne 

 and Mendel. Thirty-five rats in all were used for this experiment. 

 They were kept on this rigid diet for a period averaging about 

 three to four months, but extending in several cases five to six 

 months. In no instance were rachitic lesions noted either micro- 

 scopically or macroscopically, merely an inactive osteogenesis. 

 That the dietary in point of fact did contain only a minimal 

 amount of the fat-soluble vitamine was proved by the lack of 

 gain of the animals after they had been on this food mixture for 

 about sixty days, by their prompt response in growth on the addi- 

 tion of 6 per cent, of butter fat to the diet, and by the development 

 of ophthalmia or keratomalacia in almost all of the animals and 

 its rapid subsidence on adding butter to the dietary. In addition 

 to eye lesions the rats on a restricted diet developed many infec- 

 tions. Those receiving 0.5 c.c. of orange juice did not, however, 

 develop either ophthalmia or infections as frequently as others 

 where the diet did not include this food. Ten control animals 

 which received the same diet, with, however, an addition of butter, 

 did not develop ophthalmia, grew normally and remained in per- 

 fect health. Our deduction from these experiments is that a lack 

 of the fat-soluble vitamine in a dietary which is otherwise com- 

 plete does not lead to the development of rachitic lesions in rats. 



136 (1718) 



The effect of various modifications of a diet producing rickets 



in rats. 



By A. M. PAPPENHEIMER, G. F. McCANN, T. F. ZUCKER, 

 and A. F. HESS. 



[From the Department of Pathology, College of Physicians 

 and Surgeons, Columbia University.] 



At the March meeting of this Society, it was shown by Sherman 

 and by one of the writers of this paper that rickets regularly de- 

 veloped in rats maintained on a diet composed of patent flour, 

 calcium lactate, sodium chloride and ferric citrate. It was further 

 found that the substitution of 0.4 per cent, basic potassium 



