MECHANICAL EFFECTS OF OSMOSE ON THE PLANT. 367 
plant is directed, now more to one class of proximate in- 
gredients, as the carbohydrates, and now to another, as the 
albuminoids, although the supplies of food presented are 
uniform both in total and relative quantity. 
If a slice of red-beet be washed and put into water, the 
pigment which gives it color does not readily dissolve and 
diffuse out of the cells, but the water remains colorless for 
several days. The pigment is, however, soluble in water, 
as is seen at.once by crushing the beet, whereby the cells 
are forcibly broken open and their contents displaced. 
The cell-membranes of the uninjured root are thus appar- 
ently able to withstand the solvent power of water upon 
the pigment and to restrain the latter from diffusive mo- 
tion. Upon subjecting the slice of beet to cold until it is 
thoroughly frozen, and then placing it in warm water so 
that it quickly thaws, the latter is immediately and deeply 
tinged with red. The sudden thawing of the water with- 
in the pores of the cell-membrane has in fact so altered 
them, that they can no longer prevent the diffusive ten- 
dency of the pigment. (Sachs.) 
§ 4. 
MECHANICAL EFFECTS OF OSMOSE ON THE PLANT. 
The osmose of water from without into the cells of the 
plant, whether occurring on the root-surface, in the buds, 
or at any intermediate point where chemical changes are 
going on, cannot fail to exercise a great mechanical influ- 
ence on the phenomena of growth. Root-action, for ex- 
ample, being, as we have seen, often sufficient to overcome 
a considerable hydrostatic pressure, might naturally be 
expected to accelerate the development of buds and young 
foliage, especially since, as common observation shows, it 
operates in perennial plants, as the maple and grape-vine, 
most energetically at the season when the issue of foliage 
takes place. Experiment demonstrates this to be the fact. 
