— 107 — 



into acetone and hydrocyanic acid. Apart from the glucoside, the 

 author detected in Thalictram aquilegifolium an enzyme, which is capable 

 of decomposing both the glucoside found and amygdalin. 



Another new glucoside, prulaurasin, has been isolated by 

 H. Herissey 1 ) from the leaves of the cherry laurel (Prunus lauro- 

 cerasus L.). By extracting the leaves with boiling water, evaporating 

 the bulk of this in vacuo, diluting the residue with alcohol, filtering, 

 driving off the alcohol in vacuo, and purifying the residue, he ob- 

 tained the body in a crystalline state. It crystallises in thin colour- 

 less needles, has a slightly bitter taste, melts at 120 to 12 2°, is 

 readily soluble in water, alcohol, acetic ether, almost insoluble in ether, 

 and turns the plane of polarised light to the left ([«] D — 62,69°). 

 Emulsin splits up prulaurasin into hydrocyanic acid (8,59 °/ ), glucose 

 (61,24 °/ ), and benzaldehyde. It has the formula C 14 H 17 N0 6 , and 

 is isomeric with the amygdonitril glucoside of E. Fischer 2 ) and the 

 above-mentioned sambunigrin of Bourquelot and Danjou. It differs 

 from these two by its solubility, its melting point, and its optical 

 rotatory power. 



According to L. Guignard's 3 ) examinations, the red currant bush 

 (Ribes rubrum L.) also contains small quantities of a glucoside splitting 

 off hydrocyanic acid. From 100 gm. leaves were obtained: in June 

 when the currants were still green, 0,0035 £ m * hydrocyanic acid; a 

 few weeks later, when they were ripe, 0,0026 gm., and in the beginning 

 of August only 0,00 1 5 gm. In 1 00 gm. of the young branches which 

 only contained little chlorophyl, only small quantities could be detected, 

 and in an equal weight of roots and the ripe fruit no trace of hydro- 

 cyanic acid could be found. Of other species of Ribes, Ribes aureum 

 Pursh., behaved the same as Ribes rubrum; the quantity of glucoside 

 was only smaller. The leaves of Ribes nigrum L., Ribes uvacrispa D. C, 

 Ribes sanguineum Pursh., Ribes multiflorum Kit., Ribes subvestivum Hook, 

 et Arm, Ribes prostratum L'Her., and Ribes Gordonianum Lem., yielded 

 no hydrocyanic acid. In the leaves and twigs containing glucoside, and 

 in the roots and fruit free form glucoside of Ribes rubrum and Ribes 

 aureum, the author detected emulsin, and the like in the species Ribes 

 nigrum and Ribes uvacrispa which contain no glucoside at all. Of 

 seeds, only those of Ribes rubrum and Ribes nigrum were examined, 

 and in them the presence of emulsin was proved. 



The examination of prulaurasin compelled Herissey 4 ) to deter- 

 mine small quantities of benzaldehyde. For the separation of the 



*) Compt. rend. 141 (1905), 959, and Journ. de Pharm. et Chim. VI 23 

 (1906), 5. 



2 ) Berl. Berichte 28 (1895), T 5° 8 - 



3 ) Compt. rend. 141 (1905) 448. 



4 ) Journ. de Pharm. et Chim. VI. 23 (1906), 60. 



