The Resistance of the Antirachitic Substance in Cod Liver Oil to Reagents.*

The present communication records the first of a series of experiments begun at the suggestion of Professor E. V. McCollum on the chemical examination of antirachitic substances. The most familiar of these substances occurs in cod liver oil, and is commonly known as the antirachitic vitamin, or vitamin D. The cod liver oil which I used was an unfrozen, unadulterated oil, rendered at Bay Bulls, Newfoundland, in August, 1923. 0.20 to 0.25 per cent of this oil, incorporated with the McCollum high calcium, rickets-producing diet, No. 3143, induced advanced healing in rachitic rats in 5 days. The animals were examined by the Shipley line test procedure. The samples of oil treated with reagents were similarly triturated with Diet 3143, acetone being used as diluent. In the following records of experiments a somewhat detailed account of procedures is given. The protocols of the individual rats, however, are combined in one self-explanatory table (Table I). The rats receiving the curative preparations were kept in a moderately lighted room.. Influence of Hydrogen Dioxide on the Antirachitic Vitamin.Mellanby (l), McCollum, Simmonds, Becker, and Shipley (2), and Goldblatt and Zilva (3) have demonstrated that hot cod liver oil does not readily lose its antirachitic activity when aerated. In the present experiment I investigated the stability of the antirachitic vitamin to hydrogen dioxide-a reagent which with