124 Green. — On Vegetable Ferments. 
originally very finely granular and semi-transparent, becomes 
much coarser in appearance, the granules increasing to such 
an extent as to make the nucleus almost invisible. When 
the endosperm is becoming exhausted of its reserve material, 
the cell-contents clear again and become even more trans- 
parent than they were at first. The process of secretion in 
these epithelium-cells continues so long as they are supplied 
with a flow of nitrogenous material from the endosperm across 
the epithelium. 
Marshall Ward 1 also calls attention to the brilliant re- 
fringent granules in the cytohydrolytic drops obtained from 
the hyphae of Botryiis , which appear to be secreted from 
the protoplasm, as evidenced by their giving proteid reactions. 
These granules only appear when the hyphae are secreting 
the enzyme. Guignard 2 points out the granular character of 
the cells secreting myrosin in the root of the horse-radish. 
Similar granules occur, according to Marshall Ward and 
Dunlop 3 , in the cells of the raphe of the seeds of Rhamnus 
infectorius , in which they located the rhamnase of that plant. 
The same granular character occurs in the cells of the epi- 
thelium of the haustorium in Phoenix and other Palms. 
Constitution of the Enzymes. 
There has been much speculation as to the nature of the 
enzymes and their zymogens. From the fact of their secretion 
directly from the protoplasm and the histological changes ob- 
served in the latter during the secretory process, the opinion has 
been advanced that the zymogens are proteids from which the 
enzyme arises by a decomposition consequent on oxidation 4 . 
Heidenhain 5 suggested that the zymogen consisted of the ferment 
in combination with an albuminoid body. By many observers 
the suggestion has been made that the enzymes themselves are 
proteid bodies. Loew holds that they are proteids allied to 
the peptones, basing his opinion upon analysis of them 6 . In 
1 op. cit. 2 op. cit. 3 op. cit. 
i Vines, Physiology of Plants, p 193. 
5 P Auger’s Archiv, 1875, Bd. X, p. 581. 
6 P Auger’s Archiv, XXVII, 1882. 
