EXPERIMENTAL. 35 



THE RESIDUE AFTER DISTILLATION. 



The residue remaining after distillation of the esters weighed 57 grams. 

 This was dissolved in boiling alcohol, and after cooling 1.98 grams of needle 

 crystals were filtered out. The filtrate was evaporated to a sirup under 

 reduced pressure, saponified by heating with an excess of barium hydroxide, 

 and, after removing the barium, evaporated to small volume under reduced 

 pressure. The solution was then saturated with hydrochloric acid, and, 

 after standing on ice for a long time, yielded 7.39 grams of glutaminic acid 

 hydrochloride. The free acid prepared by evaporating with an exactly 

 equivalent quantity of potassium hydroxide, when recrystallized from water, 

 melted at 202 to 203 with effervescence. 



Carbon and hydrogen : 0.3646 gram substance, dried at 110, gave 0.5432 grain CO 3 and 

 0.2019 gram H 2 O. 



Nitrogen: 0.3696 gram substance gave NH 3 =3.55cc. HC1 (i cc. HCl = o.oi gram N). 



Calculated for C 5 H 9 O 4 N, C 40.82, H 6.12, N 9.52 p. ct.; found, C 40.63, H 6.15, N 9.60 

 p. ct. 



The total glutaminic acid obtained from leucosin was 17.5 grams, or 6.73 

 per cent. This result is higher than that recently recorded in this labora- 

 tory, namely, 5. 72.* 



This protein is one from which the glutaminic acid hydrochloride can be 

 directly obtained only with great difficulty. In the former paper attention 

 was directed to this fact, and the statement made that it is possible that the 

 result given was too low. 



TYROSINE. 



Forty grams of leucosin, equal to 34.96 grams dried at 110, were boiled 

 for 12 hours with a mixture of 120 grams of sulphuric acid and 240 grams 

 of water. After removing the sulphuric acid with an equivalent quantity of 

 barium hydroxide, the solution was evaporated with an excess of barium 

 carbonate in order to remove ammonia. After removing the barium, the 

 solution was concentrated to a small volume on the water-bath and allowed 

 to stand for some time. The substance which separated was washed with 

 cold water, dissolved in ammonia, the solution treated with bone-black, and 

 evaporated. On cooling, i .0360 grams tyrosine separated in colorless needles. 

 The filtration from this, on further concentration, yielded 0.13 gram more 

 tyrosine, making a total of 1. 1660 grams, or 3.33 per cent. This was recrys- 

 talized and analyzed. 



Carbon and hydrogen : 0.4573 gram substance, dried at 110, gave 0.9994 gram CO 2 and 

 0.2813 gram H 2 O. 



Calculated for C 9 H U O 3 N, C 59.62, H 6.13 p. ct.; found, C 59.60, H 6.11 p. ct. 



1 Osborne & Gilbert, American Journal of Physiology, 1906, xv, p. 333. 



