316 THE VITAMINS 



Diet No. 3143 



Per Cent 



Wheat 33 



Maize Zi 



Gelatin 15 



Wheat gluten 15 



NaCl 1 



CaCOa 3 



However, because differences in the phosphorus content of hard and 

 soft wheat are great enough to make the production of rickets with diet 

 No. 3143 uncertain unless soft wheat is used McCollum, Simmonds, 

 Becker and Shipley (1925) proposed the use of other diets to prepare 

 animals for the line test, e.g. : 



Diet No. 4025 Salts No. 2>7 



Per Per 



Cent Cent 



Wheat germ 5.00 CaCOa 1.50 



Salts No. 37 5.15 KCl 1.00 



CaCOa 1.50 NaCl 1.00 



Gelatin 10.00 NaHCOs 0.40 



Egg albumin 10.00 MgO 0.20 



Wheat gluten 12.00 FeS04.7H20 0.20 



Agar-agar 2.00 KH2PO4 0.85 



Dextrin 49.35 



Butterfat 5.00 5.15 



More recently (1926) they have called attention to the fact that even 

 these diets are not altogether reliable for producing rickets, because 

 butterfat introduced at a 5 per cent level to furnish vitamin A, may at 

 the same time furnish enough vitamin D to forestall rickets. 



Steenbock and Black (1925) pointed out that the protein content of 

 McCollum's diet No. 3143 is rather high, that the gelatin content is too 

 high, resulting in anorexia or diarrhea, and that the vitamin A content 

 is too low to prevent ophthalmia and infections of the respiratory tract 

 for a period long enough to allow for the depletion of the reserves of 

 the antirachitic vitamin. They recommended the use of their diet No. 

 2965 



Diet No. 2965 



Per Cent 



Yellow corn 76 



Wheat gluten 20 



CaCOs 3 



NaCl 1 



for preparing animals for the line test, because it permits greater growth 

 while shortening the period for the development of rickets, and because 

 it is easier to prepare and is cheaper. Steenbock's diet No. 2965 has 

 practically the same calcium-phosphorus relations as McCollum's 



