30 



Xitrogen in commercial, meat extracts. 



Substance. 



Nitrogen 



in precip- Proteicls 

 itatf by (Nx6.25). 

 broinin. 



Per cent. Per cent. 



Liebig Company's extract 1.41 8. 92 



Seasoned bovril 1.94 j 12.28 



Bovril for invalids 2. 64 16. 71 



Kueiiig and Boemer have shown that the proteid nitrogen in meat 

 extracts is generally much overestimated. They found a total of 1.17 

 per cent of proteid nitrogen in the Liebig Company's extract, which is 

 equivalent to 7.41 per cent of total proteids, mostly albumose. The fact 

 that broinin completely precipitates all proteid and geiatinoid matters 

 in solution, affords a convenient means of solving certain problems which 

 have hitherto presented considerable difficulty. For instance, in a solu- 

 tion which has been subjected to digestion it may be possible to precipi- 

 tate all the unchanged proteids by saturation with zinc sulphate. The 

 peptones which have been formed during digestion remain in solution 

 and can be separated by nitration. In the nitrate the peptones can be 

 completely precipitated by broinin, and thus the total quantity of these 

 bodies formed during digestion can be accurately determined. 



Allen and Searle applied this method to an examination of the Lie- 

 big Company's extract, 5 grains of which were dissolved in 100 cc of 

 water and the solution saturated with zinc sulphate. After filtering, 

 broinin water was added to the filtrate and a precipitate produced which 

 redissolved on diluting with water and the addition of hydrochloric 

 acid. When the filtrate from the saturated zinc sulphate was previ- 

 ously diluted with water and acidulated, no precipitate was formed 

 on the addition of bromiu. This reaction shows that no considerable 

 quantities of real peptones exist in Liebig's extract. 



Since this bulletin was prepared for the press, an extensive article 

 on the halogen derivatives of albumin has been published by F. Blum 

 and W. Yaubel 1 of Frankfurt, Germany. 



'Ueber Halogeneiweissderivate, Journal fiir praktische Chemie, 1897, 56, 393-6, 

 ami 1898, 57, 365-396. 







