158 



Cyanogenesis in Plants. 



This liquid, when poured into an excess of alcohol, yielded a white precipitate 

 of proteid matter, which, when dried by exposure to air on glass plates, 

 formed slightly brown, granular masses. This preparation readily decom- 

 posed aqueous solutions of amygdalin and salicin, and also of phaseolunatin 

 prepared from the seeds of Phaseolus lunatus. 



The enzyme contained in the roots of the bitter cassava evidently closely 

 resembles, and is probably identical with, the emulsin-like ferment obtained 

 by us from the seeds of Phaseolus lunatus* and also from young flax plants 

 (see this series, Part IV). 



Cassava, therefore, like the other plants producing prussic acid which we 

 have examined in the course of this investigation, contains a cyanogenetic 

 glucoside, together with an enzyme capable of decomposing it. It is remark- 

 able that the same glucoside, phaseolunatin, should occur in such different 

 plants as Phaseolus lunatus, Linum usitatissimum, and Manihot species. 



Although, for the reasons stated, we have found it convenient to employ 

 the root of the bitter cassava for the isolation of the glucoside and its 

 identification with phaseolunatin, there can be little doubt that this same, 

 glucoside occurs in sweet cassava, and that it is responsible for the production 

 of prussic acid in that plant. 



* ' Koy. Soc. Proc,' 1904, vol. 72, p. 285. 



