EXPERIMENTAL. 



79 



Fraction I was immediately evaporated on the water-bath with hydro- 

 chloric acid, the residue dissolved in alcohol, and the solution saturated with 

 dry hydrochloric acid gas. The solution was concentrated to a small volume 

 at a low temperature under a pressure of 10 mm., the residue taken up in 

 alcohol, its solution cooled to o and saturated with hydrochloric acid gas. 

 On prolonged standing 0.22 gram of glycocoll ester hydrochloric separated, 

 which melted at 144 to 145. When mixed with pure glycocoll ester 

 hydrochloride, the melting-point was unchanged. 



Chlorine : 0.1058 gram substance gave o. 1063 gram AgCl = Cl 24.86. 

 Calculated for C 4 H 10 O 2 NC1, Cl 25.40 p. ct 



Neither fraction II nor the ether distilled from the esters gave evidence of 

 glycocoll. 



This preparation of gliadin did, in fact, contain a very small amount of 

 glycocoll, which is possibly due to a slight contamination with glutenin, in 

 which there has since been found a notable quantity of this amino-acid. 



Fraction II was saponified, and the solution evaporated under highly 

 reduced pressure from a bath at 40, and the residue extracted with alcohol, 

 in which about 18 grams dissolved. 



Fraction III, by similar treatment, yielded 24 grams of alcohol-soluble 

 substance. The alcoholic solutions were united and evaporated to dryness 

 from a bath at 40. The crystalline residue, when dried to constant weight 

 in vacuo, weighed 39.59 grams. From this, by extraction with alcohol, 8.7 

 grams of substance insoluble therein were separated. 1 The total proline 

 thus found was 30.89 grains, equal to 7.03 per cent. 



1 Emil Fischer employs this method for estimating the proportion of proline in pro- 

 teins, but stated that the result obtained is too high (Berichte der deutschen chemischen 

 Gesellschaft, 1906, xxxix, p. 530). 



