Distribution of Fat-Soluble A. 



129 



Experiments were also conducted using hyoscyamin in place of 

 atropin, and others are now under way covering some of the other 

 drugs with central emetic actions. The results of all of these will 

 be detailed in the complete paper to be published later. 



72 (1136) 



The distribution of the fat soluble A, the growth-promoting sub- 

 stance of butter fat, in the naturally occurring foodstuffs. 1 



By E. V. McCollum, Nina Simmonds, and Walter Pitz 



(by invitation). 



[From the Laboratory of Agricultural Chemistry of the Wisconsin 

 Experiment Station.] 



That butter fat and egg yolk fats contain a substance whose 

 chemical nature is unknown, which is indispensable for growth or 

 prolonged maintenance of health was first pointed out by McCol- 

 lum and Davis. Later they showed the presence of this substance 

 in the maize kernel and in wheat embryo, and presented some 

 evidence that if it is found in the oat kernel it is in very small 

 amount. 2 Our further studies have confirmed these observations. 



McCollum and Kennedy 3 have discussed the desirability of 

 employing the term "fat-soluble A" for this, to distinguish it from 

 the "water-soluble B," a substance which is widely distributed in 

 the natural foodstuffs of both animal and vegetable origin and is 

 likewise indispensable for growth or prolonged maintenance. The 

 water-soluble B only is concerned with the production and cure of 

 polyneuritis in pigeons. 



Our experimental work with the grains has shown that the 

 content of the fat-soluble A is greater in the maize kernel than in 

 wheat, and greater in wheat than in the oat kernel. In all three 

 the content is too low to induce growth at the maximum rate 

 even though all other factors in the diet be near the optimum. 



1 Published with the permission of the Director of the Wisconsin Experiment 

 Station. 



2 McCollum and Davis, Jour. Biol. Chem., Vol. 15, p. 167 (1913); Vol. 21, p. 179 

 (1915); Vol. 23, pp. 181 and 231 (1915). 



3 McCollum and Kennedy, ibid., vol. 24, p. 491 (1916). 



