1906.] 



Cyanogenesis in Plants. 



147 



lysis, by heating with dilute mineral acids, or by the addition of linseed 

 meal to an aqueous solution of the glucoside, the latter was decomposed, 

 yielding hydrocyanic acid, a reducing sugar, and a volatile ketone, which 

 gave the iodoform reaction. Jorissen and Hairs also examined the enzyme 

 contained in embryonic flax plants, and observed that, whilst it had the 

 property of hydrolysing both linamarin and amygdalin, the emulsin of 

 almonds was incapable of decomposing linamarin. 



Van de Ven, who attempted to repeat the work of Jorissen and Hairs, 

 using flax seed as a source of the glucoside, did not succeed in isolating 

 linamarin, and he was also unable to find that hydrocyanic acid could be 

 obtained from the seed.* Jouck, however,f was able to confirm and extend 

 Jorissen and Hairs' observations, and identified the volatile ketone produced 

 by the hydrolysis of the flax glucoside as acetone. This author, however, 

 found, in opposition to Jorissen and Hairs, that linamarin is decomposed by 

 the emulsin of almonds. 



Prelim inary Experirn ents. 



In the present investigation, attempts were first made to utilise flax seed 

 cake (linseed cake) as a raw material for the isolation of the glucoside, but it 

 was found that, although distinct evidence of the presence of a cyanogenetic 

 glucoside in the cake was readily obtainable, the quantity present was so 

 small that it was impossible to isolate it in a crystalline condition. It was 

 considered advisable, therefore, to have recourse to the use of young flax 

 plants as a source of linamarin. The young flax plants for the investigation 

 were grown during the summer of 1905, partly at the Imperial Institute and 

 partly by permission of Professor J. B. -Farmer, F.E.S. — to whom we are 

 indebted for the help thus rendered — -at the Chelsea Physic Garden. Small 

 supplies of immature flax were also received during the earlier part of the 

 investigation from Mr. F. Barbour, of the Department of Agriculture and 

 Technical Instruction in Ireland, to whom our thanks are also due. 



As a preliminary measure, the amount of glucoside present in whole flax 

 plants, including roots, at various stages of growth was determined, with a 

 view to the selection of the richest material. This estimation was carried out 

 by completely extracting a weighed quantity of the air-dried plant with 

 alcohol, distilling the solvent from the extract, dissolving the residue in water, 

 hydrolysing the glucoside contained in this by boiling with hydrochloric 

 acid, and finally distilling off and estimating the hydrocyanic acid in the 



* Van Eijn, ' Die Glykoside,' 1900. 



t 'Beitrag zur Kenntnis der Blausaure abspaltenden Glycoside,' Inaug. Diss., Strass- 

 burg, 1902. 



