REVIEW OF THE LITERATURE. n 



Chittenden & Smith 1 prepared many samples of gluten-casein according to 

 Ritthausen's method. As an average of eight analyses they found the fol- 

 lowing composition : 



p. ct. 



Carbon 52.87 



Hydrogen 6.99 



Nitrogen 15.86 



Sulphur 1.17 



Oxygen 23. 1 1 



They also prepared and analyzed the various products of peptic digestion 

 of this protein. 



Osborne & Voorhees 2 investigated the number and character of the proteins 

 of wheat, but as their results are given in detail in the body of this paper 

 they need not here be further mentioned. 



O'Brien* recognized globulin, proteose, and the gluten-proteins in extracts 

 of wheat flour. The protein-leucosin, which Osborne & Voorhees considered 

 to be an albumin, was regarded as a globulin by O'Brien, since it is precip- 

 itated by saturating its solutions with magnesium sulphate. 



About i per cent of the flour consists of proteins soluble in saline solu- 

 tions and coagulating on boiling. Neither ferment action nor globulin take 

 part in gluten formation. Gluten consists of zymom, insoluble in alcohol, 

 and glian, soluble therein. Glian is formed by hydration of the protein of 

 the flour and zymom from glian by further hydration. Glian yields myxon, 

 glutine, and mucine, which are not constituents of glian, but derived from it. 



Frankfurt* estimated the proportion of various constituents of the embryo 

 of wheat, and found globulin 21.62 per cent and albumose 13.62 per cent. 



O'Brien 5 stated that the proteins of the wheat embryo consist of globulins 

 of themyosin type, coagulating at 55, soluble in dilute solutions of sodium 

 chloride or magnesium sulphate and precipitated by excess of these salts ; 

 globulins of the vitellin type, coagulating at 75 to 78, and soluble in dilute 

 solution of sodium chloride, but not precipitated by an excess ; proteose 

 and albumin, not coagulating below 80, soluble in sodium chloride solution, 

 but not precipitated by an excess, nor by dialysis, nor by carbonic acid. 



Kjeldahl 6 found that all of a number of preparations of the alcohol- soluble 

 protein made from wheat flour showed an almost constant content of about 

 52 per cent of carbon and 17.25 per cent of nitrogen, and when dissolved in 



1 Chitteuden & Smith, Journal of Physiology, 1890, xi, p. 419. 



'* Osborne & Voorhees, American Chemical Journal, 1893, xv, p. 392. 



3 O'Brien, Annals of Botany, 1895, ix, p. 171. 



* Frankfurt, Versuchs-Stationen, 1895, xi^vn, p. 449. 



5 O'Brien, Annals of Botany, 1895, ix, p. 543. 



6 Kj Adahl, Agricultur chemischen Centralblatt, 1896, xxv, p. 197. 



