99 
Green. — On Vegetable Ferments. 
action in that they decompose certain complex bodies known 
as glucosides, splitting off sugar from their molecules, but giving 
rise also to a variety of other bodies, many of which, so far as 
we know, are of no use in the nutrition of the plant. The pro- 
cess which they set up is in most cases, like the former, one of 
hydrolysis, the entry of water and the disruption of the mole- 
cule of the glucoside taking place simultaneously. From the 
greater complexity of the decomposition, Sachs is inclined to 
look upon the two classes of ferments as radically different 
from each other, but probably this is not the case, the com- 
plexity arising from the nature of the body hydrolysed, the 
ferment in both cases being responsible only for the actual 
hydrolysis. Thus the action of emulsin, one of these bodies, 
on amygdalin is expressed by the equation : — 
C 20 H 27 NO u + 2 H 2 0 = C 6 H 5 C 0 H + HCN + 2(C 6 H 12 O b ) 
Amygdalin Benzoic aldehyde Prussic acid Sugar. 
The best known members of this group are the emulsiri 
of the bitter almond, the myrosin of the black mustard and 
other Cruciferae, the erythrozym of the madder-root, and the 
ferment found by Marshall Ward and Dunlop in the seed of 
Rhamnus infectorius. 
Emulsin has sometimes been called synaptase. It has long 
been known to be present in certain species of Amygdalus and 
Cerasus or Prunus , from which it can be extracted in the form 
of a greyish powder. Its presence is associated with the forma- 
tion of prussic acid, especially in the bitter almond and the 
cherry-laurel. It decomposes the glucoside amygdalin accord- 
ing to the equation just quoted. For a long time its distribu- 
tion in the plant was uncertain, though it could be detected in 
all the parts where metabolism was vigorous. In 1865 
Thome 1 made some experiments upon the sweet and bitter 
almond, which led him to form the opinion that the enzyme 
existed only in the bitter variety and was localised there in the 
fibro-vascular bundles of the cotyledons. Portes 2 in 187 7 
came to the conclusion that emulsin was confined to the axis 
1 Bot. Zeit. 1865, p. 240. 
2 Portes, Journ. de Pharm. et de Chimie, t. XXVI, p. 410, 1877. 
H 2 
