October 10, 1919] 



SCIENCE 



353 



In an investigation of the nutritive proper- 

 ties of commercial oleos and tlieir ingredients, 

 the "writer and coworkers^ have found a con- 

 siderable difference in their vitamine content. 

 It is significant that of the oleo oils those 

 most highly pigmented were also the richest 

 in fat-soluble vitamine and those least pig- 

 mented were the poorest. This, in view of the 

 present prevailing conception of the impor- 

 tance of the vitamine content of certain fats 

 in the diet, is a matter of such great economic 

 significance that comment on it is reserved 

 imtil the investigations now in progress shall 

 have been completed. It is mentioned here 

 merely to indicate why it is considered pos- 

 sible that the fat-soluble vitamine may be one 

 of the yellow pigments or a closely related 

 compound. 



In scores of feeding experiments in which 

 butter fat as prepared from ordinary butter 

 has been used as the source of the fat-soluble 

 vitamine we have repeatedly observed varia- 

 tions in the vitamine content. It has not 

 been possible to correlate this with the degree 

 of pigmentation — which is well known to vary 

 with the feed and the breed of the dairy cow — 

 as the amount of natural pigment present had 

 been concealed by the addition of butter color. 

 One fact however appears particularly signifi- 

 cant, and that is, that when butter fat is 

 heated its vitamine is destroyed and simulta- 

 neously there occurs a destruction of its pig- 

 ment.' Whether this is an accidental coinci- 

 dence or one and the same thing remains to 

 be seen. 



From the evidence submitted it appears 

 reasonably safe, at least as a working hypothe- 

 sis, to assume that the fat-soluble vitamine is 

 a yellow plant pigment or a closely related 

 compound, which view, moreover, is strength- 

 ened by the fact that we know through the 

 work of Palmer and Eckles* of the inability 

 of the animal to synthesize the yellow pig- 

 ments carotin and xanthophyll. From its oc- 

 currence in butter, in leaves, in carrots and 

 in other materials known to be rich in carotin, 



3H. Steenbook, P. W. Boutwell and Hazel E. 

 Kent, Jour. Biol. Chem., 35, 517, 1918. 



*L. S. Palmer and C. H. Eokles, Jour. Biol. 

 Chem., 17, 211, 223, 237, 245, 1914. 



it might be concluded that we were here con- 

 cerned with carotin. Some data, that we 

 have accumulated have answered this in the 

 negative and it has been so reported,' but it 

 appears doubtful if much importance can be 

 attached to these earlier results as we have 

 since observed that carotin under certain con- 

 ditions is a very labile compoimd. We do not 

 desire to mislead our readers by indicating 

 that we have conclusive evidence one way or 

 another. 



Provisionally, we are assuming that the fat- 

 soluble vitamine is one of the yellow plant 

 pigments, but we are not unmindful of the 

 possibility that the reasons for the association 

 of these properties in nature, viz., yellow pig- 

 mentation and this growth-promoting property 

 may be a genetic one in some cases, while in 

 others it may be indicative of mere similarity 

 in physical if not chemical properties. If it 

 is not a pigment, no doubt, instances will soon 

 be found where it is found to occur liberally 

 in non-pigmented materials. We already have 

 indications that certain materials are as rich 

 in the fat-soluble vitamine as is yellow corn, 

 yet they are far less pigmented. Whether this 

 can be explained in difference of kind of pig- 

 ment which in yellow corn is known to be prin- 

 cipally xanthophyll or whether we are dealing 

 in these instances with the leuco compound 

 remains to be seen. 



It is scarcely necessary to elaborate on these 

 findings or to point out their possible eco- 

 nomic significance. Many investigations based 

 on the general premises which we have here 

 outlined are now in progress and will be re- 

 ported as the evidence obtained seems to 

 warrant a detailed discussion. 



H. Steenbock 



Laeoeatoey of Ageicultueal Chemistet, 

 IlNivEESirY OF Wisconsin 



THE AMERICAN MATHEMATICAL 

 SOCIETY 



The twenty-sixth summer meeting of the society 

 was held at the University of Michigan, Septem- 

 ber 2-4, in conjunction with meetings of the 

 Mathematical Association of America and the 



6 H. Steenbock, P. W. Boutwell and Hazel E. 

 Kent, Froc. Amer. Soe. Biol. Chem., 1919. 



