CHAPTER VI 

 VITAMIN D 



The medical literature of rickets is authoritatively reviewed both 

 historically and critically by Hess in his recent book Rickets, Osteo- 

 malacia and Tetany. In view of this, and of space limits here, the present 

 chapter is confined to the period and literature of the conscious investi- 

 gation of the vitamin factor. 



Mellanby, by his extended study of experimental rickets (1919), 

 showed that cod-liver oil and butterfat were effective in preventing the 

 disorder in puppies subsisting on diets consisting largely of cereal with 

 small allowances of milk. Some of his experiments indicated that 

 still other materials prevented rickets, but these results may have been 

 influenced by the puppies' preexperimental bodily storage of the anti- 

 rachitic factor, or by the inorganic relations of the food. His results 

 were, for the most part, in keeping with the view that rickets is due 

 primarily to a nutritional lack. He concluded that it is "probable that 

 the cause of rickets is a diminished intake of the antirachitic factor, 

 which is either fat-soluble A or has a somewhat similar distribution to 

 fat-soluble A." This view was adopted, although with some reservation, 

 in the British Committee report of 1919 (Hopkins, Chick, Drummond, 

 Harden and Mellanby, 1919) and was for a time so far accepted as 

 to lead some writers to include prevention of rickets as one of the 

 functions of vitamin A. 



Hess and Unger (1919-1920) held that, in their clinical experience, 

 rickets sometimes developed in infants receiving large quantities of 

 milk containing what they believed to be ample fat-soluble vitamin. 



In 1921, Sherman and Pappenheimer (1921, 1921a) showed that 

 rickets may be caused or prevented in rats by changes in the mineral 

 elements of the food. Their experimental diets were practically devoid 

 of fat-soluble vitamins; but the animals had not been depleted of 

 their bodily stores of such vitamins. 



In the same year Shipley, Park, McCollum and Simmonds (1921) 

 reported that the phosphate ion may be the determining factor in 

 certain cases ; whereas previously they had worked on the hypothesis 

 of a joint deficiency of calcium and vitamin A. 



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