Wright, Bbvis, and Nelson. — Chemistry of Flesh Foods. 4.83 



examination of the solid meat-extracts. It can therefore be assumed that 

 had the solid meat-extracts been even incipiently decomposed the method 

 would have revealed the fact. Further work on the point is being carried 

 out in order to determine the factors which inhibit the decomposition. 



Copper in Liver-extract. 



Our work in connection with meat-extracts from various sources has 

 led to the examination of extracts manufactured from edible portions of 

 the carcase other than true muscle-tissue, and it has been found that the 

 mineral salts of an extract manufactured from liver invariably contain 

 copper. Of course, if copper utensils were used in the preparation of these 

 extracts the presence of copper might be expected, but we have been able 

 to detect this metal in liver-extracts manufactured under conditions which 

 exclude the possibility of casual contamination from copper utensils ; 

 moreover, in extracts manufactured from true muscle-tissue no copper has 

 been found in the mineral salts. The presence of copper in liver has, 

 however, been recorded, notably by Aston (5) in his investigations upon 

 bush sickness, and its presence as a normal liver-constituent is also noted 

 by Haminerstein (6) and Emery and Henley (7) ; it is thus not surprising 

 to find it a normal constituent of extracts manufactured from liver. 



The presence of up to 10 per cent, of glucose is also recorded by us as 

 a normal constituent of liver-extract. 



Summary. 



1. The commercial valuation of a meat-extract based upon the per- 

 centage of the material soluble in 80 per cent, alcohol is in accord with the 

 physiological value, which depends upon the " meat-bases " present. 



2. The incipient decomposition of nitrogenous foods can be detected by 

 the determination of the percentage of ammoniacal nitrogen before such 

 decomposition is evident to the senses. 



3. A comparative study of two methods of determining ammoniacal 

 nitrogen is given. 



4. Solid extract of meat is a non-putrescible substance. 



5. In extracts manufactured from liver both copper and glucose are 

 foimd to be present. 



Literature cited. 



1. A. M. Wright, Trans. N.Z. Inst., vol. 45, pp. 1-17, 1913. 



2. ibid., vol. 47, pp. 569-72, 1915. 



3. ibid., vol. 43, pp. 1-6, 1911. 



4. T. E. Thorpe, Diet. App. Chem., vol. 3, p. 428, 1912. 



5. B. C. Aston, Trans. N.Z. Inst, vol. 44, pp. 288-98, 1912. 



6. 0. Hammerstein, Text-book Physiol. Chem., p. 367, 1911. 



7. J. A. Emery and R. R. Henley, Jour. Agric. Res., vol. 17, p. 16, 1919. 



8. Report Extract-of-Meat Commission, Lancet, Oct. 24, 1908, p. 1241. 



9. Method of Analysis, Bull 107 (rev.) U.S. Dep. Agric, pp. 9-10, 1912. 



10. Method of Analysis, J.A.O.A.C., 2, pp. 274-75, 1916. 



11. N. Henrikson and G. C. Swan, Jour. I. Eng. Chem., vol. 10, p. 614, 1918. 



12. M. Pennington and H. S. Greenlee, Jour. Am,. Chem. Soc, vol. 33, p. 561, 1911. 



13. E. D. Clark and L. H. Almy, Jour. Biol. Chem., vol. 33, pp. 483-98, 1918. 



14. K. G. Falk, E. I. Bauman, and G. McGuire, Jour. Biol. Chem., vol. 37, p. 525. 



1919. 



15. K. G. Falk and G. McGttire, Jour. Biol. Chem., vol. 37, p. 547, 1919. 



16. O. Folin, Jour. Biol. Chem., vol. 8, p. 497, 1910. 



16* 



