BY JAlIliS ir. PETItlK. 



453 



Deductions from Table A. — (1). The glucosidc in this plant is not decom- 

 pused by lioiliug with water. In most cases no hydrocyanic acid was obtained, 

 and in some a verv small amount was distilled over. The maximum quantity 

 thus obtained was 2 rags., or about 3 % of the total acid, and was pro})al)ly the 

 result of the enzyr.ie acting for a short interval Ix^lnre its complete destruction, 

 that is, before the wliole mass could be raised to the temperature of the boiling 

 water. 



(2). Boiling with dilute acids likewise results in very incomplete decom- 

 position. Two kin Is of results are apparent: in one the hydrocyanic acid slowly 

 increases per hour (\os. 1, 2 and 7), in the other the evolution comes to an end 

 in the third or fourth hour of boiling (Xos. 3, 4 and .5). Hydrochloric acid pro- 

 duces more than sul]ihuric acid. 



B. Aut.oh/sis, or Macer(itio)i nf the plcwt in icater. 



Here the glucoside comes in contact with its own enzyme, and is dccumjiosed 

 with liberation of hydrocyanic acid. Into a distillation flask fitted with its cork 

 and tubes were placed 5 — 50 gms. of leaves with 500 ecs. of water. This was kept 

 in an iiu'ubator at 40° C. for varying periods, then distilled with and witliout 

 5 % sulphuric acid 



Table B. 



Aiiiofysis of leaves. 

 Time of 

 No. maceration. Particular treatment. 



HCN. 



mgs. % 



Deductions from Table B. — (1). When the leaves are allowed to stand at an 

 optimum temperature, which in the case of most cyanogenetic enzymes is about 

 40° C, hydrocyanic acid is set free in amounts much greater than were obtained 

 with acid hydrolysis 



(2). With regard to the time of maceration, the maximum yield, as shown in 

 Nos. 8-15, was that obtained for 1 day: 45 mgs. % when distilled with sulphuric, 

 and 51 rag's. % when distilled with hydrochloric acid. 



(3). Leaves of sample ii. were dried and jiowdered at the beginning, and the 

 powder left in an o])pn tray. "When taken for expci'lments 16-18, it is shown that 



