Green . — On Vegetable Ferments. 123 
leaves of Melianthus major was inactive on starch, but that 
after standing a few days it had diastatic powers. He noted 
the same thing in the case of potato-tubers. 
Experiments of Reychler 1 , and of Lintner and Eckhardt 2 , 
point to the existence of a zymogen in the cells of the grain 
of wheat. They found that the action of a dilute acid upon 
the gluten of wheat gave rise to a diastatic enzyme. Frank- 
hause 3 found further that in germination of barley small 
quantities of formic acid could be detected in the grains. 
This may be regarded as important in discussing the increase 
of diastatic power attending germination, as it would probably 
transform zymogen into ferment. 
Though the results of histological examination of the cells 
in which the various enzymes occur are not at all complete, 
they point, so far as they go, to a similar mode of secretion 
to that obtaining in animal cells, and hence indirectly to 
an antecedent zymogen. Gardiner 4 has described the changes 
in the cells of Dionaea muscipula in the states of rest and 
activity : in the first condition the cells show a very granular 
protoplasm lining the cell-wall, leaving a single central 
vacuole, the granules being so numerous as to obscure the 
nucleus which lies at one end of the cell. After stimulation 
the leaves begin to secrete and continue to do so for twenty- 
four hours. In this second condition, that of activity, the 
protoplasm has lost its granularity, being clear and hyaline ; 
the nucleus has come to occupy the centre of the cell and 
strands of protoplasm connect it with the peripheral layer. 
The same observer shows that the gland- cells of Drosera in 
the resting state are much more granular than they are after 
secretion. 
Brown and Morris 5 describe similar changes in the cells of 
the epithelium of the barley-scutellum during the early stages 
of germination. When this process begins, the protoplasm, 
1 Reychler, Ber. 22, 414. 
2 Lintner und Eckhardt, Zeitschr. fur das gesammte Brauwesen, 1889, p. 389. 
3 Frankhause, Der Bund. Berne 37, No. 26. 
4 Proc. Roy. Soc. 1883. 5 op. cit. p. 467. 
