SCIENTIFIC PROCEEDINGS 



Abstracts of Communications. 



Seventy-third meeting. 



College of the City of New York, February 16, iqi6. 

 President Lusk in the chair. 



49 (l"3) 



Concerning the protein content of meat. 



By N. W. Janney. 



[From the Chemical Laboratory of the Montefiore Home and Hos- 

 pital for Chronic Invalids, New York.] 



The commonly accepted modes of determining the protein 

 content of animal muscle are open to criticism. Thus in such 

 standard works as that of Konig, 1 also in Atwater and Bryant's 2 

 extensively quoted tables, the protein material has been usually 

 calculated by multiplying the total nitrogen content of the fresh 

 meat in per cent, by the factor 6.25. This, as is known, intro- 

 duces a considerable source of error, for of the total nitrogen 

 about 13 per cent, is combined in non-protein substances. More- 

 over the factor 6.25 is of itself incorrect. It is obtained on the 

 basis of accepting 16 per cent, as the average nitrogen content 

 of meat proteins, whereas it has been recently established in this 

 laboratory that the correct value lies between 16.2 and 16.7 per 

 cent, of the pure muscle proteins of various species. 



A second indirect method of calculating the "protein sub- 

 stances" of meat has also been recognized by Atwater and Bryant. 

 According to this procedure the combined weights of the ether 



'Konig, J., "Chemie der Menschlichen Nahrungs und Genussmittel," Berlin, 

 1903. 



2 Atwater, W. O. and Bryant, A. P., U. S. Dept. of Agriculture, Bull. 28 (rev.), 

 1906. 



8.3 



