XI. REQUIREMENTS 381 



as shown liy the rate of growth of dentine, growth in length of the odonto- 

 blasts, and phagocytic activity and fragihty. 



a. Prevention of Gross Sympto7ns of Scurvy 



A variety of scorlMitigcnic (hets, in man}^ of which .-lutocUivod alfalfa has 

 been incorporated, have been successfully employed for determining the 

 requirements. Aged rabbit chow pellets (commerical) containing alfalfa 

 have also been so used. In recent years, however, there has been consider- 

 able difficulty in producing scurvy in the expected time with these pellets, 

 even when they are heated to destroy the ascorbic acid. The generally ac- 

 cepted explanation for this difference is that the alfalfa presently used is a 

 superior product and is dried under conditions which tend to preserve the 

 ascorbic acid. Because of these difficulties some workers in this field are 

 now using a modified form of the Sherman, LaMer, and Campbell- diet. 

 The writer has found the following modifications to be satisfactory; 



The followmg fat-soluble vitamins are added to the diet after dissolving 

 in the oil using the procedure followed by Booth et alr^ 



/3-Carotene 5 mg. 



Calciferol 1 mg. 



Vitamin E acetate 10 mg. 



Vitamin K 2 mg. 



Sherman et al} showed that gross protection against scurvy was afforded 

 by 3 ml. of tomato juice, a quantity which presumably contained about 

 0.5 mg. of ascorbic acid. In tests wdth .synthetic ascorbic acid other inves- 

 tigators have found a daily dosage of approximately 0.5 mg. to be suffi- 

 cient'" for the prevention of gross symptoms of scurvy. 



"^ H. C. Sherman, V. K. LaMer, and H. L. Campbell, J. Am. Chem. Soc. 44, 165 

 (1922). 



2» A. N. Booth, C. A. Elvehjem, and E. B. Hart, J. Nutrition 37, 263 (1949). 



3 W. A. Waugh and C. G. King, /. Biol. Chem. 97, 325 (1932). 



* E. W. Crampton, B. C. Collier, L. D. Woolsey, and F. A. Farmer, Science 100, 599 

 (1944). 



5 C. F. Dunker, C. R. Fellers, and W. B. Esselen, Food Research 7, 260 (1942). 



«J. L. Svirbely and A. Szent-Gyorgyi, Biochem.. J. 27, 279 (1933). 



^ L. Randoin, Conipt. rend. soc. biol. 116, 4 (1934). 



8 G. F. Gothlin, Nature 134, 569 (1934). 



' A. Giroud, C. P. Leblond, and R. Ratsimamanga, Yale J. Biol. Med. 9, 573 (1937). 

 '« A. Djabri, Z. Vitaminforsch. 10, 210 (1940). 

 " E. W. Crampton, J. Nutrition 33, 491 (1947). 



