435 



were put into consumption complaints of injury to and death of 

 stock poured in from all sides. Investigation by Messrs Tatlock 

 & Thomson, of Glasgow, revealed the fact that these beans, which 

 closely resembled the beans of Phaseolus lunalus, a plant grown in 

 Mauritius, Burma and elsewhere, yielded on steeping with water 

 notable quantities of Prussic Acid, and there can be no doubt that 

 the conclusion of these chemists, confirmed in many cases by other 

 analysts, the author included, that the deaths must be referred to 

 Prussic Acid poisoning was correct. The fact that the beans of 

 Phaseolus lunatus at times developed poisonous properties had been 

 well recognised for a long time, and the matter had been investi- 

 gated at the Imperial Institute by Prof. Dunstan, who, on examining 

 the beans from Mauritius, discovered that the Prussic Acid did not 

 actually exist in the beans, but that under suitable conditions the 

 beans were capable of yielding Prussic Acid, the original of which 

 was traced to a glucoside, to which the name Phaseolunatin was 

 given, and a ferment which was able to decompose the glucoside 

 with formation of Prussic Acid. 



The fact that Java Beans may be deadly poisonous caused che- 

 mists generally to investigate a number of other beans and seeds 

 to ascertain whether they possessed cyanogenetic properties similar 

 to Java Beans, and the results obtained have been most interesting 

 and instructive. 



It has long been known that Tapioca root produced Prussic 

 Acid, and when taken in an untreated condition was poisonous; 

 but it was not generally known that a large number of seeds in 

 common use possessed similar properties, although to a less marked 

 extent. 



All the beans from Java which were examined yielded Prussic 

 acid when steeped in water at a suitable temperature, the quan- 

 tities found ranging from 0.012 per cent, to 0.137 per cent. Ta- 

 king the highest quantity (0.137 P er cent.) the Prussic Acid capable 

 of being yielded by 10 Ibs. of the beans is 95 grains, and as one 

 grain of Prussic Acid is regarded as a fatal dose in man it is 

 evident that when the conditions are favourable to the productior 

 of the full amount of Prussic Acid such beans would prove highly 

 poisonous. 



The beans from Mauritius examined by Dunstan, Henry and 

 Auld yielded amounts of Prussic Acid varying from 0.041 per cent, 

 to 0.088 per cent., while the beans from Burma varied from 0.004 

 per cent, to 0.024 per cent, for the pale brown with purple spots, 

 and nil to 0.027 per cent, for the cream white beans. 



