12 



heated rapidly, melts with decomposition at 208 ; when heated slowly 

 it remains unchanged up to 170 , and becomes brown (without it 

 being possible to determine a melting point) at 180 . The mass 

 heated to 180 had a resinous character, and contained 4,09 °/ 

 nitrogen, whereas amygdalin only contains 3 °/ . The product, however, 

 still yielded with emulsin hydrocyanic acid. 



A work by E. Bourquelot and H. Herissey 1 ) deals with the 

 conditions of isomerism of the five known hydrocyanic acid gluco- 

 sides: amygdalin, Dakin's isoamygdalin , Fischer's amygclonitrile 

 glucoside, sambunigrin, and prulaurasin, which under the action of 

 emulsin are all decomposed into d-glucose, hydrocyanic acid, and 

 benzaldehyde, that is to say, yield oil of bitter almonds. We would 

 only refer here to the original treatise. 



R. J. Caldwell and S. L. Courtauld 2 ) have investigated the 

 hydrolysis of amygdalin by acids, with special regard to the behaviour 

 of amygdalin towards enzymes, so that their work also throws light 

 upon the reaction taking place during the production of oil of bitter 

 almonds. Ludwig had first established that the action of hot dilute 

 hydrochloric acid gives results analogous to those of emulsin, but 

 up to the present no information had been given on the rapidity 

 of the hydrolysis effected by acid. The authors found that if 

 normal hydrogen chloride is employed, the hydrolysis at a measur- 

 able rate only takes place at 6o° and above, and for this reason 

 they made their experiments at 60 to 8o°. The results show that, 

 although amygdalin is finally split up by acid into hydrocyanic 

 acid, benzaldehyde, and 2 mol. glucose, the glucose is split off in 

 two stages ; by careful hydrolysis it is possible to obtain as an 

 intermediate product the mandelonitrile glucoside which Fischer 

 obtained from amygdalin by the action of yeast- extract. The sac- 

 charobiose radical in amygdalin has in the hydrolysis by acid, under 

 the same conditions, at least six times the resistance of maltose. 



The same authors 3 ) interested themselves in the question whether 

 Fischer's mandelonitrile glucoside obtained by them in the hydrolysis 

 of amygdalin, must be regarded as a glucoside corresponding to amyg- 

 dalin, or as a mixture of stereo-isomerides corresponding to isoamyg- 

 dalin. It is well known that amygdalin is converted by alkalis into 

 isoamygdalin. The authors obtained from mandelonitrile glucoside, 

 by the action of barium hydrate, the isomeric prulaurasin, which 

 possesses a higher rotatory power than Fischer's glucoside derived 



1 ) Journ. de Pharm. et Chim. 26 (1907), 5. 



2 ) Journ. chem. Soc. 91 (1907), 666. 

 8 ) Journ. chem. Soc. 91 (1907), 671. 



