New York Agricultural Experiment Station. 289 



of organic and inorganic phosphorus would vary widely in differ- 

 ent feeding stuffs. Were this the case and assuming that the 

 synthesis of nucleo-proteids could only occur in the plant, it is 

 easy to see how there might be found along this line of inquiry 

 some important distinctions in the value of certain cattle foods 

 when used for specific purposes. These were the hypothetical 

 considerations fundamental to this inquiry. 



It was obviously necessary to first inquire concerning the pro- 

 portion of inorganic phosphorus in cattle foods and the results 

 already reached indicate strongly, as I believe they demonstrate, 

 the absence of any appreciable amounts of inorganic phosphorus 

 in unmodified plant tissue, particularly seeds and grains. This 

 being true, the point of view which was first held is somewhat 

 modified. We must still inquire whether any ration sufficient in 

 quantity would contain an amount of available phosphorus-bear- 

 ing proteids equal to, or greater than, the amount necessary for 

 the formation of milk or eggs at the usual rate, and, therefore, 

 attention is naturally directed to differences which may exist in 

 such proteids as to availability and function. For instance, such 

 an inquiry as this is pertinent: Does the proportion of easily 

 hydrolyzable phosphorus-bearing proteids in a food have any rela- 

 tion to its efficiency for milk or egg production? It is believed 

 that such inquiries as these are not only profitable but necessary 

 to a solution of certain nutrition problems. We have made, and 

 are still making, great advances in knowledge by the aid of the 

 respiration apparatus, which gives us largely a measure of end 

 results, but equally important are studies of function and relation, 

 which must be carried on, in part at least, through following the 

 transformations and cleavage changes which occur during diges- 

 tion and assimilation, at the same time that we measure the 

 influence of varying conditions of nutrition upon production. 



The earlier methods of experiment and research, such as feeding 

 experiments where the metabolic changes are not followed, must 

 now be recognized as no longer competent to solve the more im- 

 portant fundamental problems related to animal nutrition. There 

 are values and factors which such experiments neither define nor 

 measure and if we are to make real progress we must give more 

 attention to studies of underlying facts. 



W. H. Jordan. 



