502 
The Seed and its Germination. 
paste, containing about one per cent, of starch, and exposing it 
to a temperature of about 104° Fahr., the starch gradually 
vanishes, and the mixture is found then to contain a quantity of 
sugar proportionate to the starch which has disappeared. 
The changes in the cellulose are not capable at present of 
such absolute proof. The ferment can be prepared in a similar 
way, and its solution will dissolve cell walls. If a thin section 
of a piece of potato be immersed in such a solution, in a few hours 
the walls of the cells are found to become swollen and gradually 
to dissolve. A piece of filter paper, consisting of cotton fibre, 
which is composed of cellulose, is found to be affected similarly, 
though more slowly. But at present the nature of the resulting 
product has not been fully ascertained, though there is little 
doubt that it is again a form of sugar. 
That these changes, brought about by extracts of the ger- 
minating grains, are due to the ferments thus prepared is shown 
by the fact that the solutions lose their power of action if they 
are subjected to a high temperature, a phenomenon we have 
seen to be one of the peculiarities of unorganised ferments. 
In both cases we have thus the transformation of an 
insoluble and indiffusible substance into forms which are soluble 
and diffusible, the same process in fact which we call digestion 
in an animal organism. 
More than that, there is evidence that the sugars thus 
produced are materials upon which the young embryo feeds. 
Messrs. Brown and Morris have fully established this point by 
dissecting out young embryos, whose growth has just recom- 
menced, and feeding them on solutions of the different sugars. 
They absorbed these and continued to grow and to develop, 
much as when left surrounded by their endosperms. The pro- 
cess of absorption of the nutritive matter was found to be 
carried out by the same epithelium of the scutellum, which thus 
is seen not only to be secretory in function, but absorptive as 
well. The utilisation of the cellulose in the seeds of palms also 
depends upon an epithelium covering the absorbing organ, 
which in this case is a part of the cotyledon. The details are 
not yet, however, fully understood. 
The way in which the absorbed carbohydrate becomes part 
of the actual substance of the young plant we will discuss after 
we have considered the changes in the nitrogenous reserve 
materials and the forms in which these also are absorbed. 
The nitrogenous reserve materials have already been 
described as existing very largely in the form of definite bodies 
known as aleurone grains. These have been investigated in 
greatest detail in the lupin and a few other leguminous seeds. 
