THE RELATION OF THE FAT-SOLUBLE VITAMINS (A AND D) TO THE DEVELOPMENT OF EX PERIMENTAL RICKETS IN RABBITS

EXPERIMENTAL results have been at some variance as regards the etiological interdependence of the fat-soluble vitamins with calcium and phosphorus in rickets. The production of rickets in puppies by a diet deficient in fat-soluble vitamins (Mellanby) followed by a demon stration of the relationship of this factor to calcium and phosphorus metab olism (McCollum, Simmonds, Shipley and Park; Sherman and Pappen heimer; Korenchevsky), has stimulated attempts to define the relative im portance of these factors in the production of experimental rickets. Mellanby concluded that rickets developed in puppies whose diets were deficient only in the antirachitic fat-soluble organic factor. Attempts to produce rickets in guinea pigs (Tozer), kittens (Mackay), and pigs (Zilva, Golding, Drummond and Coward), by feeding a diet deficient only in the fat-soluble vitamins, failed. Korenchevsky and also Goldblatt produced rickets in rats by a diet deficient only in the fat-soluble vitamins, although Shipley, Park, McCollum and Simmonds, and Hess, McCann and Pap penheimer concluded that there must be a deficiency both of the fat-sol uble vitamin and of calcium or phosphorus to produce rickets in rats. Rickets has been produced in the rabbit by diets deficient in fat-soluble vitamin, low in phosphorus, and high in calcium (Goldblatt and Moritz). It was considered of interest then to observe the effects of a diet deficient only in the fat-soluble vitamins (A and D) on the degree of calcification of the bones and the development of rickets in rabbits and at the same time to repeat the experiment on rats. EXPERIMENTAL Diet. The basal diet used was essentially the same as that used for the production of rickets in rats by Korenchevsky and by Goldblatt. This diet was eaten readily by the rabbits; only 4 of the 30 observed refused to eat. Each animal received daily 5 grams of alcohol- and ether- extracte