192 



Scientific Proceedings (68). 



While a hypersensitive state probably takes some part in the 

 inception of the infection, these experiments indicate that the 

 subsequent exudative lobar involvement is essentially a progres- 

 sive and cumulative process. 



Il6 (1048) 



The nitrogen distribution of some feedstuffs and cereals. 

 By J. F. Brewster and C. L. Alsberg. 



[From the Department of Agriculture, Washington, D. C] 



The importance of knowing the amino acid content of feed- 

 stuffs has led the authors to apply Van Slyke's method 1 for the 

 analysis of proteins direct, without previous isolation of the 

 proteins themselves. The fine-ground and well-mixed material is 

 weighed off in amount equivalent to 2-3 grams protein (estimated 

 from the N-content) and completely hydrolyzed with 20 per cent, 

 hydrochloric acid. Thereafter the method of Van Slyke is 

 followed. 



Analyses of corn, corn germ, cottonseed flour, kafir corn, 

 tomato seed (pressed) and peat have been completed, results in 

 duplicate agreeing well. The authors have had difficulty in 

 accounting for the sulphur of the protein, the results for cystin 

 being lower than was expected. This difficulty has been experi- 

 enced by others and it is generally believed that if the cystin 

 grouping be present, it is decomposed on hydrolysis and the sulphur 

 changed to a form not precipitated by phosphotungstic acid with 

 the cystin fraction. It is also conceded that sulphur exists in 

 protein in other than the cystin grouping. 



The results show Kafir corn and tomato seed meal to be lacking 

 in histidin. Qualitative tests for tryptophan are positive for 

 tomato seed, positive but slight for Kafir corn. Osborne and Clapp 2 

 found tryptophan and lysin, 2.93 per cent, in glutelin extracted 

 from corn by weak alkali. The same investigators found neither 

 lysin or tryptophan in zein of corn. Osborne's feeding experi- 

 ments with cottonseed globulin show this protein to be satis- 



1 Jour. Biol. Chetn., X, 15. 1911. 



1 Amer. Journal of Physiology, 20, 477. 1907. 



