Green. — On Vegetable Ferments. 135 
tartaric, &c., instead of acetic, lactic, butyric, &c. This may 
however be due to the character of the metabolism of the two 
classes of cells respectively, for the action is intracellular in 
both cases. Alteration of the conditions in which the cells are 
living may modify profoundly such metabolism, as we shall 
presently see. The power of the protoplasm to effect the 
disruption of carbohydrates is seen in the transformation and 
reconstruction of the transitory starch which is constantly 
going on in various parts of the higher plants, though no 
doubt in many cases here diastase takes part. The same 
power can be noted in the changes found to take place 
among the various sugars that the higher plants contain. 
Brown and Morris 1 have shown not only that cane-sugar is 
transformed into glucose and laevulose, but that it is also recon- 
structed during the growth of the embryo when germination 
has begun. They say that cane-sugar can always be detected 
in the embryo when artificially nourished on various culture- 
solutions, though not a trace of it be supplied in the culture- 
medium itself. 
From a consideration of these phenomena it seems difficult 
to resist the conclusion that in both higher and lower forms 
we have to deal with what has been called the fermentative 
power of the protoplasm, and that the results that we note in 
connection with the working of the so-called organised ferments 
are only the expression of this activity, or in other words of 
the varying metabolism of the cells. The lower forms do not 
differ from the higher ones in possessing special powers, but 
only in not being able, from their want of differentiation, to 
show the division of labour which is so advantageous, if not 
necessary, to the latter. All the metabolic processes must be 
carried out in the unicellular organism in the same mass of 
protoplasm. 
Returning to Nageli’s two points of difference between the 
action of organised and unorganised ferments, we have seen 
that the first of them can no longer be supported. From 
bacteria enzymes of several descriptions have been isolated ; 
1 op. cit. p. 517. 
