206 VITAMIN D GROUP 



warranted deduction, occasionally seen in medical literature, that vitamin 

 D3 is the vitamin D of cod liver oil. It has been shown by Matterson et al.^^^ 

 and by Waddell and Kennedy^-^ that, when vitamin D3 and cod liver 

 oil are standardized with chicks kept on a diet in which most of the phos- 

 phorus is inorganic (e.g., the A.O.A.C. diet), and then again assayed with 

 chicks or turkey poults kept on a diet in which most of the phosphorus is 

 phytic, the vitamin D3 is found to be much more effective than the vitamin 

 D of cod liver oil. This can mean only that vitamin D3 is not the dominant 

 vitamin D of cod liver oil and that the dominant form (or forms) of vitamin 

 D in cod liver oil is something different from any recognized form. 



(5) In determining the efficacy ratios of the liver oils of twentj^-five species 

 of fish, Bills et al.^^^ found a few oils with a ratio much above 100. The ex- 

 treme example was the liver oil of the white sea bass, Cynosdon nobilis, 

 which had a ratio of about 300. This oil, when subjected to molecular dis- 

 tillation,'^^ showed an exceptionally pure elimination curve, indicative of a 

 preponderance of one form of vitamin D. If the assays can be confirmed, 

 it will be established that white sea bass liver oil contains a new form of 

 vitamin D characterized by the highest known efficacy ratio. 



(6) Windaus and Trautmann^^" and Dimroth and Paland'*^ briefly men- 

 tion the irradiation product of 22,23-oxidoergosterol. Described only as a 

 feebly active product, this is presumably 22,23-oxidocalciferol. 



(7) Windaus and Buchholz*" have prepared an oily ketone of vitamin D2 

 which was probably uncontaminated with traces of the vitamin, and which 

 exhibited about 3^oo o^ the potency of the vitamin in tests with rats. 



(8) McDonald ^^^ has found that by the irradiation of 7 -hydroxy choles- 

 terol (or an impurity associated therewith) a slight antiricketic potency is 

 developed. Conceivably, the irradiation causes dehydration, with the for- 

 mation of traces of 7-dehydrocholesterol, in which case the vitamin pro- 

 duced would not be a new form, but merely D3. 



(9) Weinhouse and Kharasch^" claim to have produced a form of vitamin 

 D by irradiating the heated reaction product of 7-ketocholesteryl acetate 

 and isobutyl magnesium bromide. 



(10) In the section headed Chemical Structure and Activatability, men- 

 tion was made of the vitamin D from 7-dehydrocampesterol. Corresponding 

 to the structure of its precursor, this vitamin can be regarded as the C-24 

 epimer of vitamin D4. 



(11) The vitamin D from epiergosterol is, presumably, epicalciferol. 



323 L. D. Matterson, H. M. Scott, and E. P. Singsen, J. Nutrition 31, 599 (1946). 

 3" J. Waddell and G. H. Kennedy, /. Assoc. Official Agr. Chemists 30, 190 (1947). 

 326 A. Windaus and K. Buchholz, Hoppe-Seyler's Z. physiol. Chem. 256, 273 (1938). 



326 F. G. McDonald, cited by C. E. Bills, The Vitamins, Chapter xxiii. American 

 Medical Association, Chicago, 1939. 



327 S. Weinhouse and M. S. Kharasch, /. Org. Chem. 1, 490 (1936). 



