366 Prof. H. E. Armstrong and Mr. E. Horton. [Mar. 3, 



From this point of view, it is possible that a distinct enzyme — an 

 acetcyanase — is operative in separating the nitrilic radicle from phaseolunatin 

 and that this, rather than a simple /8-glucase, is the main constituent of the 

 active product from Phaseolus beans ; but if such be the case, the enzyme 

 must be compatible with the cyanophoric radicle in Fischer's glucoside, whilst 

 the corresponding enzyme in emvilsin must be incompatible with the nitrilic 

 member of phaseolunatin. 



Although we have been able to verify Eosenthaler's statements as to the 

 synthetic activity of almond-emulsin, we have been unsuccessful in preliminary 

 experiments with phaseolunatase in obtaining evidence that this enzyme cau 

 induce the interaction of benzaldehyde and hydrogen cyanide. This result 

 apparently affords additional proof that the almond and the Pliaseolus 

 enzymes are possessed of distinctive properties. The problem afforded by 

 " emulsin " is one which can only be solved by exhaustive study of 

 enzymes from various sources. In conjunction with Dr. E. F. Armstrong, 

 we have for some time been engaged in developing a method of standard- 

 ising the enzymes relatively to a series of reference compounds, so that a 

 strict comparison may be made of the activities of materials from various 

 sources. 



[To contrast the behaviour of vegetable cijUisc — which may be regai'ded 

 provisionally as identical with cellasc, the enzyme by which the /8-glucoside 

 cellobiose is resolved into two molecules of glucose* — with that of almond 

 emulsin and of tlie Pliaseolus enzyme, we have ascertained the effect pro- 

 duced on several cyanophoric glucosides by an extract prepared by digesting 

 ground oats witli three times their weight of water during about 15 hours. 

 A mixture of the extract with an equal volume of a 4M/10 solution of the 

 glucoside was digested at 37° during 48 hours. The amount of change was 

 8 per cent, in the case of Fischer's glucoside, 5 per cent, in that of amygdalin 

 and 4 per cent, in the case of the Phaseolus glucoside. Tlie greater sensitive- 

 ness of this last in comparison with amygdalin, when the results are compared 

 with those produced by emulsin, is perhaps noteworthy and suggestive. 



We may also refer to J esuits obtained with an extract of the seeds of the 

 kidney vetch, Anthyllis vxdncraria, whicli contains an enzyme of the emulsin 

 type. To test its activity the ground seed was macerated with about four 

 times its weight of water. An M/f) solution of the glucoside containing half 

 its bulk of this extract was digested at 37° duiing 24 hours. The amount of 



* Cf. E. FiHclier and (;. Ze)iipl6n, ' A niiiik'ii,' 190!), vol. .305, ji]). 1— G ; licrtiaiul aiuli 

 Holderer, 'Coinpt. Kond.,' 1910, vol. 160, p. 230 ; Pringsheiiii and Zempl6u, 'Zeit. Physiol. 

 (;hfin.,' 1909, vol. (52, p. 307. 



