102 Green, — On Vegetable Ferments. 
matter, and aleurone-grains, though situated in various regions 
among cells containing one or more of these constituents. 
They contain, associated with their protoplasm, a quantity of 
amorphous proteid matter which is coagulated by alcohol and 
then separates from the peripheral protoplasm in the form of 
coarse granulated masses, which are coloured by Millon’s 
reagent a more vivid red than is the protoplasm. They can 
be distinguished among the parenchyma-cells in which they 
lie by staining with methyl-green and other anilin-dyes. 
Usually they are very slightly larger than the surrounding 
cells, being longer and less regular in shape. 
Guignard finds these special cells distributed in all the parts 
of the plant, those found in the seed being the richest in 
ferment. In the root they exist in the parenchyma of the 
cortex and of the bast ; in some cases also in that of the wood ; 
in the stem they may be found generally everywhere, but 
especially in the pericycle ; in the leaves they are disposed in 
the same way as in the stems which bear them ; in the carpels 
much as in the leaves ; in the ovule especially in the external 
integument. In the developing embryo these cells may be 
first detected at the time when its tissues begin to receive their 
deposits of reserve materials. 
As in the case of the almond, the glucoside is deposited in 
different cells from those which contain the enzyme. 
Guignard demonstrated the presence of the ferment in these 
cells most easily in the Wall-flower, where they form a readily 
separable layer in the pericycle. Isolating this with great 
care, and warming it with a weak solution (2 per cent.) of the 
glucoside, the characteristic odour of sulphocyanate of allyl 
was at once perceptible. He found throughout his experi- 
ments that any tissue containing these cells could effect the 
decomposition, but that if these were not present, the tissue 
could not act upon the glucoside. 
Myrosin appeas to be capable of acting on all the glu- 
cosides which the various cruciferous plants contain, yielding 
characteristic results in each case. 
The optimum temperature for its activity is a little below 
