Green. — On Vegetable Ferments. 103 
50° C. ; above that point it is less powerful and is destroyed at 
about 70° C. 
The action of myrosin is peculiar, as the intervention of 
water is not necessary for the decomposition which it sets up. 
Rhamnase. A third ferment belonging to this group has 
a more limited distribution than either of the two already 
described. It occurs in the seeds of Rhamnus infectorins , the 
so-called £ Persian berry,’ a species whose fruits yield a yellow 
dye. This ferment, which may be called rhamnase , has been 
investigated by Marshall Ward and Dunlop 1 . The fruits 
contain a glucoside x author hamnin, to which the formula 
C 48 H 66 0 29 has been ascribed. When decomposed, it yields 
rhamnetin or rhamuin and glucose. If the pulp of the fruits, 
or an extract of the pericarp, is treated with an extract of the 
seeds and kept at 35 0 C. for a short time a copious yellow 
precipitate falls, which consists of the rhamnin, the sugar 
remaining in solution. Boiling the extract of the seeds 
destroys its power of producing the precipitate. Very careful 
histological investigations proved that rhamnase is confined to 
the raphe of the seed, which is composed of parenchymatous 
cells, containing a brilliant oily-looking, colourless substance. 
The cells contain two or three large vacuoles, in which a few 
brilliant granules can be observed. The glucoside, as in the 
other cases, does not exist in the same cells as the enzyme, 
but is confined to the pericarp and pulp of the fruit, in which 
it is very abundant. The rhamnase can be extracted from the 
raphe, either by water or glycerine. 
Besides these glucoside-splitting ferments several others 
are known to occur, but they have not been so completely 
examined. The Erythrozym of madder-root has already been 
mentioned. Others are referred to by Schiitzenberger 2 as 
being found in various plants. One of them is capable of 
decomposing phillyrin, a glucoside present in the bark of 
P hilly rea latifolia , and populin, from the bark of the Aspen. 
Another splits up tannin into gallic and elagic acids and sugar. 
1 Annals of Botany, vol. I, 1887. 
2 On Fermentation. Internat. Scientific Series, vol. XX. 
