The condition in which the sugars and other soluble substances exist in
the cane is that of solution in water. The sweetish liquid is contained,
like the juices of plants generally, in cells. The walls of these cells
are porous. It has long been known that if a solution of sugar in water
be placed in a porous or membraneous sack, and the sack placed on water,
an action called osmosis, whereby the water from the outside and the
sugar solution from the inside of the sack each pass through, until the
liquids on the two sides of the membrane are equally sweet. Other
substances soluble in water behave similarly, but sugar and other
readily crystallizable substances pass through much more readily than
uncrystallizable or difficultly crystallizable. To apply this properly
to the extraction of sugar, the cane is first cut into fine chips, as
already described, and put into the diffusion cells, where water is
applied and the sugar is displaced.
[Illustration: Fig. 1--APPARATUS FOR MANUFACTURE OF SORGHUM BY THE
DIFFUSION PROCESS.]