106 VITAMINS A AND CAROTENES 



cobalt, accelerate the oxidative destriiction in fish liver oils.^- Ultraviolet 

 irradiation^^ produces the same results. Extensive researches on the en- 

 zymatic oxidation of carotene, for which the presence of unsatm^ated fatty 

 acids is necessary, have been published. ''^-^'' 



Many fatty oils originating from plants contain natural antioxidants, 

 but in most cases they are added during the process of preservation. The 

 tocopherols,*^^ palmitoyl ascorbic acid, hydi'ociuinone,'^^ gossypol, and oth- 

 gj.y69-7i ^j.g used for this purpose. In ordei' to preserve the biological potency 

 of foods they must l)e stored at the lowest temperature possible. On the 

 other hand, it is necessary to destroy enzymes by heating (autoclaving) for 

 a short time before drying foods.''- The production of dried eggs must also 

 be done with the greatest care. About 30 to 50 % of the vitamin A is 

 destroyed if the egg yolk is dried in the ortlinary way; vacuum drying under 

 carbon dioxide reduces the loss to 5 to 7 %." 



VII. Effects of Vitamin A Deficiency and Hypervitaminosis A 



in Animals 



S. BURT WOJ.JiACH 



A. GENERAL CONSIDERATIONS 



The morphologic effects of vitamin A deficiency are found in many epi- 

 thelial structures and in epiphyseal cartilage of growing bones. These 

 effects in young animals are present before the rate of growth is materially 

 retarded and may be regarded as specific or primary consequences of the 

 deprivation. Administration of vitamin A in great excess (250 to 1000 

 I.U. per gram) in an early period of growth results in a remarkable acceler- 

 ation of epiphyseal cartilage cell sequences and of the remodeling of bones 

 which normally accompany skeletal growth. 



^2 W. Heimann, Deut. Lebcnsm. Rundschau 43, 85 (1947). 



63 T. A. Chalmers, T. W. Goodwin, and R. A. Morton, Nnturr 155, 513 (1945). 



" J. B. Sumner and A. L. Bounce, Enzymologia 7, 130 (1939). 



«5 H. Siillmann, Helv. Chim. Acta 24, 646 (1941). 



«6E. L. Hove, Science 98, 433 (1943). 



6' L. O. Buxton, Ind. Eng. Chem. 39, 225, 1171 (1947). 



68 H. N. Holmes, R. K. Corbet, and E. R. Hartzler, Ind. Eng. Chem. 28, 133 (1936). 



63 E. L. Hove, /. Biol. Chern. 156, 633 (1944). 



""> P. B. Miiller, Mitt. Gebiete Lebensm. u. Hi/g. 39, 275 (1948). 



" H. L. Mitchell, W. G. Schrenk, and H. il. KiiiK, l////. Gebiete Leben.'^m. u. Hi/g. 



41, 570 (1949). 

 " R. C. Mills and E. B. Hart, ./. Dairg Sci. 28. 339 (1945). 

 ^3 G. Wendland, Vitainine u. Honnone 5, 46 (1944). 



