METABOLISM 5 81 



By the use of the proper experimental animals, the influence of a diet deficient 

 in any one of the seven essential dietary factors may be readily demonstrated. 

 Typical dietary demonstrations of this character are outlined on the following 

 pages. 



i. Influence of Vitamine Deficiency. As a result of the work of different 

 experimenters, certain "accessory food substances," "growth-promoting 

 substances," or vitamines, as they are variously termed, have been shown to be 

 of great importance in nutrition. The exact character of these substances has 

 not been established. These are two distinct growth-promoting vitamines, one 

 soluble in fats and called "Fat-Soluble A," the other soluble in water and 

 called "Water-Soluble B." The third accessory food substance is an anti- 

 scorbutic vitamine called " Water-Soluble C." These three substances have a 

 rather wide distribution as shown by the following table : 



DISTRIBUTION OF THE THREE VITAMINES 1 



important vitamine references follow: 

 Funk, Casimir: Journal of Physiology, 43, 395, 1911. 

 Hopkins, H. Gowland: Journal of Physiology, 44, 425, 1912. 

 McCollum, E. V., and Davis, M.: Jour. Biol. Chem., 15, 167, 1913. 

 Osborne, Thomas B., and Mendel, Lafayette B.: Jour. Biol. Chem., 15, 311, 1913; 



24, 37, 1916 (other references cited here); 32, 309, 1917; 34, i7> 1918. 

 McCollum, E. V., and Simmonds, N.: Jour. Biol. Chem., 33, 303, 1918. 

 McCollum, E. V., Simmonds, N., and Parsons, H. T.: Jour. Biol. Chem., 33, 411, 1918. 

 Osborne, Thomas B., and Mendel, Lafayette B.: Jour. Biol. Chem., 35, 19, 1918. 



