16 THE BOOK OF BUTTER 



cod-liver oil ' and the liquid part of beef-fat,^ contain 

 this "accessory substance." Several vegetable fats have 

 been studied. Of these the substance vital to the growth 

 of animals has been found only in the embryo of wheat 

 seeds, but in quantities too small to serve in the normal 

 growth of any animal. 



The proper name for this growth-producing substance 

 has been a puzzling problem. McCollum and Kennedy ^ 

 state that Funk proposed the name " vitamine " for this 

 type of substance. McCollum and Kennedy, however, 

 do not like this term. In fact, they consider it erroneous. 

 They suggested the terms "fat-soluble A" and "water- 

 soluble B " for the two classes of unknown substances con- 

 cerned in inducing growth. They contend that these 

 terms have the merit of not attributing extravagant values 

 to these bodies, and they differentiate between the sub- 

 stances or groups of substances only with respect to their 

 solubility relations, which is the only basis of differentia- 

 tion known at present. 



This growth-producing fat-soluble factor does not de- 

 teriorate when the butter is held in storage ■* nor when it is 

 heated with live steam for two and one-half hours,^ which 



1 Osborne, T. B., and Mendel, L. B., The Influence of Cod- 

 liver Oil and Some Other Pats on Growth, The Jour. Biol. Chem., 

 Vol. 17, p. 401, 1914. 



2 McCollum, E. v., and Davis, Marguerite, The Influence of 

 Certain Vegetable Pats on Growth, The Jour. Biol. Chem., Vol. 

 21, p. 179, 1915. 



3 McCollum, E. v., and Ke.inedy, C, The Dietary Paotors 

 Operating in the Production of Polyneurites,' The Jour. Biol. 

 Chem., Vol. 24, No. 4, p. 491, 1916. 



* Osborne, T. B., and Mendel, L. B., The Stability of the 

 Growth-Promoting Substance in Butter Fat, The Jour. Biol. 

 Chem., Vol. 24, No. 1, p. 38, 1915. 



, ' Osborne, T. B., and Mendel, L. B., Further Observations of 

 the Influence of Natural Fats upon Growth, The Jour. Biol. 

 Chem., Vol. 20, pp. 37 and 384, 1915. 



