COMPOSITION AND POOD VALUE OF BUTTER 15 



Table VII — Continued 



The above table shows that butter is one of the cheapest 

 foods at 35 cents a pound, and that it cannot be considered 

 a luxury at 45 or 50 cents a pound. 



12. Growth-promoting substances. — Another feature 

 in relation to food value of butter that has recently 

 been discovered is of extreme importance in nutrition. 

 It has been known for many years that certain foods, 

 such as milk, cod-liver oil and eggs, are of special value 

 to the growth of animals. The exact source of this growth- 

 producing power has attracted the attention of biochem- 

 ists, and as a result there have been important findings. 

 According to Osborne and Mendel,^ the growth-promoting 

 substance of milk is found in the butter-fat. This is sub- 

 stantiated by McCollum and Davis.^ It seems that a few 

 other animal fats, such as egg-yolk-fat,' *'"^* kidney-fat,' 



1 Osborne, T. B., and Mendel, L. B., Influence of Butter-fat 

 on Growth, The Jour. Biol. Chem., Vol. 16, pp. 423-432, 1913. 



2 MoCoUum, E. V., and Davis, Marguerite, Observations 

 on the Isolation of the Substance in Butter-Fat Which Exerts 

 a Stimulating Influence on Growth, The Jour. Biol. Chem., 

 Vol. 19, p. 248, 1914. 



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

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

 21, p. 179, 1915. 



