322 Prof. Armstrong, Dr. Armstrong, and Mr. Horton. [Apr. 2, 
character from those for lactase. Attention was directed, however, to 
Pottevin’s statement that Aspergillus niger contains an enzyme capable of 
hydrolysing 8-glucosides, but not 8-galactosides nor milk-sugar. In No. X 
(B, vol. 79, p. 360) some of the statements made in earlier studies were 
rectified and it was announced that evidence had been obtained that the 
activity of ordinary emulsin is due, as the French workers had contended, to 
the presence of a distinct enzyme capable of hydrolysing -galactosides, on 
which emulsin proper has no action, this enzyme affecting only @-glucosides. 
While admitting this to be the case, however, we may point out that the 
conclusions we have to bring forward involve merely a different reading of the 
facts: the facts have been correctly advanced on both sides. 
The explanation of the difference in the interpretations arrived at is simply 
that Kephir-lactase and emulsin-lactase are distinct enzymes—the one being 
a galacto-lactase, tne other a gluco-lactase: the former being controlled by 
galactose, the latter by glucose. Probably, therefore, hydrolysis is effected in 
consequence of the attachment of the one enzyme to the glucose section and 
of the other to the galactose section of the biose. 
In No. LX (B, vol. 79, p. 350) of these studies, proof was given by Messrs. 
Caldwell and Courtauld of the existence in yeast of a specific enzyme, 
amygdalase, capable of hydrolysing the bioside amygdalin into amygdonitrile- 
glucoside and a single molecule of glucose: 
C,H ,CH(CN)O—Ci2H21 0 + H,O — CsH,CH(CN)O—C;H105+ CeB20s. 
3ut amygdalin is resolved by emulsin into two molecules of elucose and one 
of the benzylidenecyanhydrol; this latter being unstable in presence of water 
decomposes into hydrogen cyanide and benzaldehyde. If both junctions were 
severed by one and the same enzyme, the effect produced would be one 
entirely sai generis, so far as our knowledge extends. From this point of 
view, the behaviour of emulsin is of special importance and has engaged our 
attention during several years past. 
By systematically studying the action of acids on amygdalin, Messrs. 
Caldwell and Courtauld were led to discover that the two glucose sections of 
the molecule are more readily separated from one another than is the 
benzylidenecyanhydrol; they succeeded in verifying this conclusion by 
isolating Fischer’s glucoside—as the compound of the cyanhydrol with 
glucose is termed—-from the product obtained on partially hydrolysing 
amyedalin. 
We have endeavoured to follow the course of change under the influence of 
emulsin. The analytical difficulties experienced at first were very serious, | 
and trustworthy results were obtained only after long study of the methods. 
