1903'.] Cyanogencsis in Plants. 289 



Hydrolysis of Phaseolunatin by Acids. 



The hydrolysis was usually effected by heating the glucoside in 

 aqueous solution with dilute hydrochloric acid at 100 C under a reflux 

 condenser. The resulting solution had a strong odour of hydrocyanic 

 acid and afforded a distillate giving the usual reactions of this sub- 

 stance. This distillate also gave a precipitate of iodoform on the 

 addition of an alkali hydroxide followed by solution of iodine. The 

 hydrocyanic acid was removed by conversion into Prussian blue, which 

 was filtered off, the filtrate made slightly alkaline and distilled until 

 the iodoform reaction was no longer obtained. To the distillate, 

 hydroxylamine hydrochloride and a slight excess of sodium carbonate 

 were added and the mixture after standing 2 hours shaken with ether. 

 The ethereal liquid was separated, dried thoroughly over calcium 

 chloride and allowed to spontaneously evaporate. A colourless 

 crystalline substance then remained which melted at 58, and had the 

 characteristic odour of acetoxime. The latter is, however, not a satis- 

 factory derivative for the identification of such small quantities of 

 acetone as were present, and recourse was therefore had to the pre- 

 paration of dibenzylidene acetone. To some of the purified distillate 

 freed from hydrocyanic acid in the manner indicated were added a few 

 drops of a 10-per-cent. aqueous solution of potassium hydroxide, 

 followed by a similar quantity of benzaldehyde and sufficient ethyl 

 alcohol (free from acetone) to produce a clear solution. This mixture 

 on standing became cloudy, and in a few hours deposited a crop of 

 golden yellow lamellae which melted at 112 and exhibited all the 

 properties of dibenzylidene acetone (m.p. 112). 



The remainder of the distillate was neutralised and evaporated to a 

 small volume, decolorised with animal charcoal and examined in a 

 polarimeter. The observed rotation was dextrorotatory, but the dark 

 colour of the solution precluded a quantitative determination of its 

 amount. When heated with a little phenylhydrazine at 100 C. 

 this liquid afforded an osazone, which when recrystallised from alcohol 

 melted at 206 (phenylglucosazone melts at 206). 



Estimation of Sugar produced by Acid Hydrolysis. 



0'1746 gramme of the glucoside was dissolved in 100 c.c. of water. 

 Portions of this solution were heated with dilute hydrochloric acid at 

 100 for varying periods. It was found that under these conditions 

 about 2 hours were required for complete hydrolysis. 



