454 



CTAXOdEXKSIS IX PLAXTS, 



the yield is practically the same tVom July to October. Leaves of sample iii. 

 were powdered separately for each expei-iment, and here again the yield is almost 

 constant during the entire period of one year. 



(4.) Sample ii., collected in midwinter, yielded the same amount of liydm- 

 cyanic acid as the sample iii., collected in the summer, in the same locality. 



C. Auloli/sis with added enzyme. 



The object of these experiments was to determine whether there existed in 

 the plant sufficient enzyme for the complete hydrolysis of its giucoside. It has 

 been stated already that when the plant-enzyme was destroyed by boiling water, 

 the giucoside could still be hydrolysed by adding the enzyme prepai-ed from sweet 

 almonds. In these experiments "emulsin" was added simply as grated almonds. 



The method was the same as in the previous series. — The leaf-powder with the 

 emulsin added was macerated with water in an incubator at 40° C. for 1 day, 

 then distilled by boiling in a cun-ent of air. 



Throughout series B and C, the whole of the liberated hydi-ocyanic acid -was 

 obtained in li hour's distillation. 



Table C. 

 Aii/olrsis -icitlt euiii/siii. 



HCN. 



Deductions from 'I'able C. — (1), It is seen at once, from the greatly inci'Ciised 

 yield of hydrocyanic acid in all samples, that tlio jilant was deficient in its 

 enzyme. 



(2.) The maximum amount was ol>tained by addition of 30 gms. of enmlsin, 

 wliidi liberated tlii' very large amount of hydrocyanic acid (No. 27) coiTesponding 

 to 0.328 % of the leaves. Therefore by addition of emulsin during the nmcera- 

 tion of the leaves the yield of hydrocyanic acid was increased alnuist tlireefold in 

 samples ii. and iii. 



(3) . The amount nt enzyme is important also. A snudl quantity was not 

 able to liydrolyse unlimited amounts of giucoside, for in the case of sample ii., 

 Nos. If) and 27, the lilicraticm nt ttic addHinnal 9 mgs. nl' hvdrocvanic acid fronj 



