158 MEDICINAL HERBS AND POISONOUS PLANTS 



nuiii poisoning which are continually occurring. In most 

 canes in which a medical man is called to attend, it is 

 the seeds that have been eaten. The signs of Laburnum 

 poisoning are vomiting, pains in the stomach, and general 

 prostration. The active principle is an alkaloid called 

 cytisine, of which there is about 3 per cent in the seeds. 

 This substance has a bitter and acrid taste, and causes 

 dilatation of the eye-pupil. 



The Almond Qroup (Amygdalae). — The Almond tree 

 itself is not a native of this country, although it flowers 

 and even forms fruit in the South of England; better 

 x*epresentatives are the Laurel, Peach, and Sloe. This 

 group calls for careful study, as an insidious poison 

 is to be found in most of its members. Fortunately 

 the fruits of all, with the exception of the Laurel, are 

 not only non-poisonous, but furnish nutritious foods. 

 The poison resides chiefly in the leaves; or rather, a 

 substance called amygdalin is found in the leaves w^hich 

 is not poisonous itself, but under certain circumstances 

 becomes changed into prussic acid. The chemical change 

 which takes place is as follows: — 



Amygdalin + Water ~ Benzaldehyde 



+ Glucose + Prussic Acid, 



This chemical change can take place only if a ferment 

 called emulsin is present. This ferment does not itself 

 take part in the reaction, but supplies, as it were, the 

 energy, wathout which the reaction cannot take place- 

 Any plant, or part of a plant, therefore, which forms 

 amygdalin must be regarded with suspicion, for in the 

 metabolism of the plant, in the natural course of events, 

 at some period, emulsin must also be produced; for 

 amygdalin, which is a reserve food-material, is of no 

 use to the plant until it has been changed into glucose, 

 no more than starch Is of any use to our own bodies 



