270 EXPEKIMENT STATION RECORD. 



This shows that considerable progress has been made in studying 

 these substances, and tliat we liave more data than might be supposed 

 on which to base a change of protein factor for certain classes of feeding 

 stuffs. In this country we are indebted to Dr. T. B. Osborne, of the Con- 

 necticut State Station, for most valuable contributions along this line, 

 and the importance of his work is thoroughly appreciated abroad. 

 Next to Eitthaiisen, the compilation shows that his investigations have 

 been more numerous than those of any other chemist. 



Out of 98 preparations given in the list only 16 contain less than 16.5 

 percent of nitrogen, and 2 of these are not well identified substances. 

 On the other hand, 54 contain over 17.5 per cent of nitrogen and 38 of 

 these contain over 18 per cent. Professor Eitthausen proposes to change 

 the factor for different groups of feeding stuffs in accordance with the 

 data at hand, using 5.7 for the protein of most cereal and leguminous 

 seeds and 5.5 for lupine and oil bearing seeds. For a few exceptional 

 cases mentioned, 6 is suggested as the most accurate factor. It is shown 

 that, compared with the use of the universal factor 6.25, the above fac- 

 tors give very considerable differences in the protein. With cereals 

 this difference is something like 1 per cent, and with the common oil 

 cakes it is from 3.5 to 5.5 per cent. For instance, the protein of cotton- 

 seed cake calculated by the old factor is 44.05 per cent, and by the new 

 factor (5.5) 38.83 per cent, a difference of 5.22, which is of considerable 

 moment in estimating the feeding value or computing rations of this 

 material. 



It is recognized that for many kinds of food and feeding stuffs insuf- 

 ficient work has been done to warrant adopting a new factor, and for 

 such Professor Eitthausen advises continuing the use of the old factor. 

 A continuation of the investigations on different classes of feeding 

 stuffs is of the highest importance to the development of the science 

 of nutrition. Furthermore, the determination of the nonalbuminoid 

 nitrogen should be a more common ])ractice, especially in the case of 

 materials whose composition is not already well known. In ascertain- 

 ing the right factor for protein these nonalbuminoid materials, which 

 in case of some feeding stuffs constitute a considerable proportion of 

 the total protein, will necessarily have to be taken into account. Their 

 approximate amount has been estimated for a considerable number of 

 feeding stuffs and some work has been done in identifying their con- 

 stituents. From what we already know it is evident that the varia- 

 tion in the nitrogen content of these constituents is greater even than 

 in case of the albuminoids. For instance, the theoretical nitrogen con- 

 tent of asparagin is about 21 per cent, of betain less than 12 per cent, 

 and of cholin about 11^ per cent. But this work has been fragmen- 

 tary, and there is abundant opportunity for a systematic investigation 

 of the amount and natnre of the nonalbuminoid constituents of vari- 

 ous feeding stuff's, not to mention studies of their food value and their 

 function in nutrition. 



