— i7 — 



give even a guess at the further course of the market. In any case 

 the quotations of our almond oil pressed from apricot kernels, 

 which as a result of large stocks we have been able to reduce slightly, 

 are scarcely likely to undergo a further reduction within the near future. 

 The prices of essential oil of bitter almonds have remained un- 

 changed, and the fact that we are never able to accumulate any 

 stock of this article is sufficient proof that we are gradually succeeding 

 in maintaining our position in competition with cheap and adulterated 

 qualities. 



With regard to the theories on the course of the decomposition 

 of amygdalin by emulsin, represented by Feist and Rosenthaler 

 respectively and referred to in our last Report x ), further communications 

 have been published by both authors. 



K. Feist 2 ) is unable to see in Rosenthaler's experiments a dis- 

 proof of his view that in the course of the splitting -up, primarily 

 d-benzaldehyde cyanohydrin is formed. He regards the action of the 

 emulsion as a reversible catalytic process : d - benzaldehyde cyano- 

 hydrin -j- emulsin "^__ benzaldehyde -f- prussic acid -(- emulsin. 



L. Rosenthaler 3 ) asserts that he merely regards Feist's proofs 

 as insufficient, leaving the question of the accuracy of Feist's theory 

 an open one. In another detailed treatise on asymmetric syntheses 

 effected by enzymes 4 ) he reports more fully on his researches, of the 

 results of which the following is a synopsis: — 



The synthesis of d-benzaldehyde cyanohydrin from benzaldehyde 

 and prussic acid by the action of emulsin is effected by a constituent 

 (s-emulsin) which differs from that upon whose action the hydrolysing 

 property of emulsin is based (d- emulsin). This s-emulsin possesses 

 enzymatic characteristics and as regards its action an optimum could 

 be found according to time and temperature. Apparently the s-emulsin 

 is either used up in the synthesis, or it passes into an inactive phase. 

 During the experiment it was not decomposed by chloroform or benz- 

 aldehyde, although the last-named combination showed noxious effects. 

 In any case, the reaction (the course of which was influenced by varying 

 quantities of the reagents and by variations in the execution of the 

 experiments), proceeds as follows. In the first place the prussic acid 

 enters into a loose combination with the optically active constituent 

 of the emulsin; next the benzaldehyde attaches itself to the residual 

 prussic acid of the compound, forming an asymmetric carbon atom; 



*f Report November 1908, 14. 



2 ) Arch, der Pharm. 246 (1908), 509. 



8 ) Ibidem 710. 



4 ) Biochemische Zeitschr. 14 (1908), 238. Quoted from a copy kindly sent to us. 



