New York Agricultural Experiment Station. 23 



At present, studies in animal nutrition are turning from what 

 may be called bookkeeping with the animal organism, that is, a 

 study of balances of matter and energy, to researches concerning 

 the specific reactions of individual compounds upon the animal 

 organism, and it is along this line that we may expect the most 

 useful future progress in the knowledge of feeding animals. 



Some seven years ago, the writer instituted investigations that 

 were intended, as their primary object, to get additional data, if 

 possible, concerning the relation between the production in the 

 milch cow of the phosphorus-bearing body in the milk, known as 

 casein, and the supply in the food of certain phosphorus-bearing 

 compounds. In attempting to carry on such an investigation, it was 

 found desirable to compare a ration having a high phosphorus 

 content with one low in phosphorus, even lower than the demands 

 of a producing cow. This led to the leaching of wheat bran with 

 a slightly acid solution in order to reduce the phosphorus content 

 to the lowest possible limit, this so-called " washed bran " to consti- 

 tute a considerable part of the low phosphorus ration. In compar- 

 ing a ration containing unwashed bran with one containing washed 

 bran, marked physiological differences in effect were observed, 

 these differences being the following : 



1. Drier and much firmer feces with the washed bran ration, 

 accompanied by a constipated condition, requiring in some cases 

 the use of a purgative. 



2. A marked disturbance of appetite (in Experiment 3) when 

 a sudden change was made from the washed bran ration to the one 

 containing the unwashed bran, indicating some specific physiolog- 

 ical influence of the compound or compounds removed from the 

 bran by leaching. 



3. A greatly reduced flow of urine following a change from the 

 unwashed bran to the washed bran ration, the reverse taking place 

 when a reverse change was made. 



4. An increase in the flow of milk consequent upon the with- 

 drawal from the (ration of the phytin and other water-soluble con- 

 stituents of bran. 



