VIII. EFFECTS OF DEFICIENCY IN ANIMALS 309 



that the ascorbic acid oxidase sj'stem may serve to generate energy-rich 

 phospliate by the oxidation of phosphoascorbate or it may "alter the prop- 

 erties of the plasma membrane by increasing the potential difference across 

 the membrane. This could l)e accomplished by maintenance of ascorbate in 

 the oxidized form at the cell surface if it is largely in the reduced form in the 

 cell interior. It is also conceivable that this enzjone plays some specific, 

 though as yet unknown role in the organized, active growth of the primary 

 wall which may control cell enlargement." 



b. In Animals 



In the absence of ascorbic acid in the diet, very young guinea pigs suc- 

 cumb so suddenly that a retarding effect on growth is often not observ- 

 able.^^'' Anderson and Smith^^^ were the first investigators to eliminate in- 

 anition as a factor in the weight differences of animals receiving, 

 as compared to those not recei\dng, ascorbic acid. In paired-feeding experi- 

 ments they showed that guinea pigs given antiscorbutics (vitamin C had 

 not been identified at this time) and whose food consumption w^as isocaloric 

 with that of scorbutic animals attained a greater weight. Cohen-^^ dem- 

 onstrated that with a deficiency of ascorbic acid in the diet of guinea pigs 

 there is first either a loss in weight or a failure to make a satisfactory gain 

 in weight, then a failure to increase in length, and finally a failure to reach 

 maturity. McHenry et al.-" studied the effect of the pure xntamin on the 

 weights of guinea pigs using the paired-feeding method and found that the 

 animals recei\'ing ascorbic acid were significantly heavier than those given 

 only the basal diet. Since the differences in weight could not be caused by 

 differences in food consumption, the suggestion was made that the lack of 

 ascorbic acid had caused alterations in metabolism, water balance, and 

 food absorption. They found that the appetite could be maintained by as 

 little as 0.1 mg. of ascorbic acid per day. In a continuation of these studies 

 Sheppard and ]\IcHenry''* found that lack of ascorbic acid caused a dimin- 

 ished retention of water, which largely accounts for the observed differences 

 in body weight. They also noted that the deficient animals in the paired- 

 feeding groups retained considerately more body fat. 



Because of the low requirement of ascorbic acid for the maintenance of 

 appetite, it is not difficult to conduct growth tests with minute doses of 

 the Wtamin. In fact this method has been used by several investigators as 

 a means of assajdng for the vitamin in foodstuffs. Dunker el al.-^^ conducted 



"♦ B. Cohen and L. B. Mendel, /. Biol. Chem. 35, 425 (1918). 



"" W. E. Anderson and A. H. Smith, J. Biol. Chem. 61, 181 (1924). 



»'« M. B. Cohen, Ain. J. Diseases Children 60, 636 (1940). 



'" E. W. McHenry, E. J. Reedman, and M. Sheppard, Biochcm. J. 32, 1302 (1938). 



2'» M. Sheppard and E. W. McHenry, Biochem. J. 33, 655 (1939). 



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



