436 



Beans obtained from France and Madagascar and Haricot and 

 Butter beans obtained in the United Kingdom yielded practically 

 no Prussic Acid. 



The Red Rangoon or Burma Beans yielded small quantities of 

 Prussic Acid, but most of the samples of White Rangoon Beans 

 examined have yielded at most only small quantities. As there do 

 not seem to be any cases of poisoning from the use of Burma 

 Beans, it is to be presumed that the quantities of Pru ssic Acid 

 produced in the ordinary course of feeding are insufficient to have 

 any marked toxic effects. 



A curious fact has been noted with regard to the cultivation 

 of the wild seeds of Phaseolus lunatus. In the wild state the seeds 

 are purple and very poisonous, but on cultivation the colour is 

 gradually modified, until at last the seeds become white, and with 

 the change of colour the poisonous character of the seeds di- 

 sappears. 



As far back as 1888, it was shown by Jorissen and Hains that 

 ground Linseed in contact with water yielded Prussic Acid; but 

 in view of the fact that Linseed, both in the ground state and 

 pressed into cake, had been used largely as cattle food with highly 

 satisfactory results, the discovery was regarded as having more of 

 a scientific interest than practical bearing. 



In the light of his researches at the Imperial Institute on Java 

 and other Beans, Prof. Dunstan has investigated the cause of the 

 production of Prussic Acid in Linseed, and finds that it is brought 

 about by the interaction of a glucoside and ferment identical with 

 the cyanogenetic glucoside and ferment of the beans of Phaseolus 

 lunatus. From two samples of Linseed Cake he was able to pro- 

 duce 0.035 P er cent - an d 0.041 per cent, of Prussic Acid, and he 

 points out that these quantities are about 50 per cent, greater 

 than those obtained from Burma Beans. He suggests, however, 

 that the heat to which the Linseed is raised in the manufacture 

 of the cake destroys the ferment and thus prevents the immediate 

 production of Prussic Acid, and it is to this that he attributes the 

 practical absence of poisoning among cattle. The fact that the 

 quantities of Prussic Acid mentioned above were produced in quan- 

 tities which might prove fatal, but it would only be by long soak- 

 ing in cold or tepid wather that the production would take place. 

 In practice the cake is usually fed dry, and in that case the enzyme 

 which produces the poison would be destroyed, or if used for calf 

 feeding it is mixed to a gruel with boiling or hot water, which 



