EXPERIMENTAL. 



69 



Nitrogen; 0.6094 gram substance, dried at no , gave NH 3 = 5.75 cc. HC1 (1 cc. HC1 

 = 0.0100 gram N) =9.43 p. ct.; calculated for C 5 H 9 N0 4) 9.48 p. ct. 



From the mother-liquors which yielded this glutaminic acid there were 

 further separated, by saturating with hydrochloric acid and proceeding in 

 the manner already described, 4.055 grams of well-crystallized hydrochloride, 

 which contained 7.73 per cent of nitrogen. 



Nitrogen: 0.4983 gram substance, dried at no, gave NH 3 = 3.85 cc. HC1 (1 cc. HC1 

 = 0.0100 gram N) = 7.73 p. ct. N ; calculated for C 3 H 9 N0 4 HC1, 7.64 p. ct. N. 



The free glutaminic acid corresponding to this amount of the hydro- 

 chloride is 3.244 grams, making a total of 1 1.724 grams. Since the 50 grams 

 of air-dry gliadin were equivalent to 46.33 grams dried at no, this amount 

 of glutaminic acid is equal to 25.3 per cent, or about the same proportion as 

 Ritthausen found in his preparation of ' ' mucedin ' ' after decomposing with 

 sulphuric acid, but much more than the 19.81 per cent found by Kutscher 

 in the same substance. The amount, however, was only about two-thirds 

 as much as that found after decomposing with hydrochloric acid, and 

 although the separation was not complete there was no reason to suppose 

 that more remained in the mother-liquors in one case than in the other. It 

 is possible, however, that the very large precipitate of barium sulphate that 

 formed on removing the sulphuric acid retained a considerable part of the 

 glutaminic acid even after extensive washing with hot water. 



In conclusion, the results of these determinations are here brought together 

 that they may be more readily compared : 



Table 16. Percentage of glutaminic acid yielded by gliadin. 



All these are minimal figures, since in each case some glutaminic acid 

 still remained in the mother-liquors, but it does not seem probable that more 

 than relatively insignificant quantities were thus lost. 



From these results it would appear that Kutscher' s determinations of 

 glutaminic acid fall far short of the actual quantity of this substance yielded 

 by the alcohol-soluble protein of wheat, and that they therefore afford no 



