Cyanogenesis in Plants. 315 



5. On account of the variable and low results obtained with clotted 

 blood, it may be inferred that the method of Nicloux may give low results 

 when applied to organs or tissues which do not disintegrate when boiled 

 with acid alcohol. We take this opportunity of stating that the expenses of 

 the foregoing work were defrayed out of a grant made by the Royal Society. 



Cyanogenesis in Plants. Part VI. — On Phaseolunatin and the 

 Associated Enzymes in Flax, Cassava, and the " Lima Bean" 



By Professor Wyndham E. Dunstan, M.A., LL.D., F.R.S., T. A. Henky, 

 D.Sc. (Lond.), and S. J. M. Auld, Ph.D. (Wurzburg). 



(Received February 27,— Read February 28, 1907.) 



In a previous paper of this series* it has been shown that the production 

 of prussic acid by the seeds or beans (" Lima beans ") of Phaseolus lunatics is 

 due to the interaction of a cyanogenetic glucoside, phaseolunatin, with an 

 enzyme, both these substances being proved to exist in the seeds. 



Phaseolunatin was proved to have the composition and constitution of 

 a dextrose ether of acetonecyanohydrin, but it was not then obtained in 

 sufficient quantity to ascertain precisely the structure of the dextrose residue 

 in the glucoside. Recently, however.f large supplies of " Java beans " (the 

 beans produced by Phaseolus lunatics grown in Java) have been imported into 

 this country, and we are indebted to Dr. Bernard Dyer for a small consign- 

 ment of these beans, which has constituted the raw material from which 

 the considerable quantities of phaseolunatin required in the course of the 

 present investigation have been prepared. 



Since the publication of our previous paper, it has been asserted by Kohn- 

 AbrestJ that these " Java beans " contain not one, but several cyanogenetic 

 glucosides, and that none of these yield acetone on hydrolysis by hot dilute 

 mineral acids or by the glucosidolytic enzymes present in the beans. 



We have considered it necessary, therefore, to examine carefully the 

 glucosidic product obtained from "Java beans" by the process originally 

 used by us§ in the investigation of the beans of Phaseolus lunatus obtained 

 from Mauritius and we have been unable to detect the presence of any other 

 cyanogenetic glucoside in Java beans except phaseolunatin, identical in all 



* Dunstan and Henry, ' Koy. Soc. Proc., 5 1903, vol. 72, p. 285. 



t ' Bulletin of the Imperial Institute,' 1905, vol. 3, p. 373, and 1906, vol. 4, p. 329. 



% ' Comptes rendus,' 1906, vol. 143, p. 182. 



§ Dunstan and Henry, loc. cit. 



VOL. LXXIX. — B. 2 A 



