168 



Scientific Proceedings (120). 



With a good test object now available in the rat made rachitic 

 on the phosphorus low diet described by Sherman and Pappen- 

 heimer, the problem of determining the point in question is much 

 easier. The rickets of children and the experimental rickets in 

 rats both respond in the same manner to treatment with cod-liver 

 oil 1 and there is no reason to believe that the substance active 

 in the two cases should not be the same. 



We first isolated the crude bases according to Gautier and 

 Morgues and found them inactive. Next the oil was hydrolyzed 

 with sodium hydroxide and the fatty acids separated. The fatty 

 acids, when reasonably purified were entirely inactive, although 

 in one of the first experiments a rather impure fatty acid fraction 

 did slightly promote calcification. The residue of unsaponifiable 

 matter gave a marked curative action. From this the bases were 

 again isolated and these bases obtained after hydrolysis were also 

 inactive. From the unsaponifiable matter in solution in alcohol 

 a goodly portion of the cholesterol was crystallized out. This 

 cholesterol fraction also was inactive. The material freed from 

 most of the cholesterol was now more active than before. In this 

 manner, we obtained fractions which on being diluted with ninety 

 parts of cotton-seed oil, which had been found to be inactive, 

 gave a curative effect a little stronger than the original cod-liver 

 oil. The results were controlled by both X-ray of tibia and 

 histological examination of rib sections. 



This material also contains the fat soluble factor A, as we 

 have been able to cure with it ophthalmia produced by deficiency 

 of fat soluble. Very recently, Steenbock, Nelson and Hart 2 

 have made similar other extracts of saponified cod-liver oil and 

 reported curative effects on ophthalmia in dogs. Although there 

 is no longer any good reason to believe that rickets is a simple 

 fat soluble deficiency, 3 the relation of the fat soluble A factor 

 to the curative property of cod-liver oil remains to be worked out. 



To sum up, we may say that the antirachitic substance of cod- 

 liver oil can be demonstrated in the ether soluble "unsaponifiable" 



1 Shipley, Park, McCollum, Simmonds and Parsons, Jour. Biol. Chem., 1920- 

 21, xlv. 343- 



'Steenbock, Nelson and Hart, Am. Jour. Physiol., 1921, lvii, 14. 



• Pappenheimer, McCann and Hess, Jour. Biol. Chem., 1921, xlvii, 395. 



* Shipley, McCollum and Simmonds, Jour. Biol. Chem., 1921, xlix, 399. 



