VITAMINS 277 



oats and a control group of a ration of the same chemical 

 composition, but blended of corn, oats, and wheat. 

 Young heifer calves were used, weighing 350 pounds 

 and as near alike as possible. They were given all the 

 salt they cared for, and allowed to exercise in an open lot 

 free of vegetation, but the diet was absolutely restricted 

 aside from salt (NaCl) to the particular ration. Dif- 

 ferences failed to develop until after a year or more 

 of time had elapsed. At that time the corn-fed animals 

 were in much superior condition to all the others, even 

 the control group. The wheat-fed ones were in the 

 worst condition of all. Body condition, milk produc* 

 tion, and the bearing of young paralleled one another in 

 demonstrating the distinction between the diets. 



This experiment marked the entrance of McCollum 

 into a field which was to make him one of the important 

 contributors to the vitamin hypothesis. He began 

 the study of the cause of the failure of animals to grow 

 on mixtures of purified foodstuffs in 1907 and employed 

 the domestic rat as the experimental animal. In 1909, 

 McCollum introduced a new feature by seeking to in- 

 crease the variety of foodstuffs in the diet as far as 

 possible, but every organic component of the diet was 

 required to be pure and free from phosphorus in any 

 form, practically the only source of phosphorus in the 

 diet being finely ground tricalcium phosphate. The 

 paper in which the results were published is important, 

 for it reported the first successful growth experiments 

 with a food supply which was at the time considered to 

 be composed only of foodstuffs which could be named. 

 It seemed to demonstrate the adequacy of the views 



