PRUSSIC ACID IN WILD CHERRY LEAVES 



119 



A marked difference was found between the quantity of acid 

 obtained from leaves wilted in bright sunlight, and the yield 

 from leaves wilted in darkness, the former condition producing 

 the larger amount. 



TABLE II. 



COMPARISON OF RESULTS FROM WILTING IN SUNLIGHT AND IN 



DARKNESS. 



Choke Cherry 

 Leaves. 



100 grams. 



Milligrams acid. 



Calc. in 



fresh 

 material. 



Calc. on 



wt. after 



wilting, j 



Black Cherry 

 Leaves. 



100 grams. 



Milligrams acid. 



Calc. in 



fresh 

 material. 



Calc. on 

 wt. after 

 wilting. 



After wilting to : 



75 per ct. orig. wt.; 

 sunlight 



65 per ct. orig. wt.; 

 sunlight 



73.5 per ct. orig. 

 wt.; darkness — 



70 per ct. orig. wt.; 

 darkness.. 



After wilting to : 



78.5 per ct. orig. 

 wt.; sunlight 



78.5 per ct. orig. 

 wt.; mod. light.. 



75 per ct.orig. wt.; 

 darkness 



66 per ct.orig. wt.; 

 sunlight 



62 per ct. orig. wt.; 

 darkness 



232. 

 213. 

 187. 

 186. 

 118. 



I 294. 

 271. 

 250. 

 282. 

 190. 



One of the most important points to be noted in connection 

 with this subject is the influence that the condition and stage of 

 growth have upon the amounts of hydrocyanic acid occurring 

 in the leaf. 



The larger, tenderer, and more succulent the leaf, the greater 

 the amount of acid that can be developed from it. To such an 

 extent is this true, that when we come to consider the dry, 

 woody leaves from full-grown shrubs or trees, we find the 

 quantity of acid they yield to be so little as to render them 

 nearly harmless. The young shoots which come up along the 

 walls, where the custom prevails of mowing the brush every 

 two or three years, are much the richest in the poison-yielding 

 substance. 



In the case of the black cherry, analyses were made from 

 four different kinds of growth : (a) large, juicy leaves from 

 suckers ; (b) large, vigorous leaves from a young tree ten feet 



