500 
The Seed and its Germination. 
molecule of the body they attack, with the assumption by it of 
water. Thus starch, the molecule of which may be represented 
for purposes of illustration by the formula C 6 H 10 O 5 , under the 
action of the ferment of saliva is transformed into sugar, whose 
molecule is 0 G H 12 O 6 , the two differing by a molecule 1 of water, 
H 2 0. 
Though these ferments have long since been demonstrated 
to be the active agents in digestion in animals, their existence 
in the vegetable kingdom has only within recent years been 
proved, and even now comparatively little is known as to many 
of them. It has, however, been ascertained that germination is 
a process which is mainly set up by them and is dependent upon 
their working. It is, in fact, the process of digestion, and 
assimilation by the seed, of the food materials deposited within 
or near the embryo. We will examine the processes of this vege- 
table digestion and absorption separately, dealing with the three 
great classes of foodstuffs — carbohydrates, proteids, fats — one by 
one, taking for discussion in each case 
a plant which shows it most easily. 
The carbohydrates, as they are 
called — starch, sugar, and cellulose 
— form the first group, and their 
transformations can be studied best 
in the grasses and cereals, of which 
we will consider barley as the type. 
The details of the germination of 
this plant have been recently worked 
out by Messrs. Brown and Morris. 
The grain of the barley has 
Fig. U.-EpUhsUum and suh- * lreac }? bee ? l eSC ? ed - f Se ^° n ° f 
jacent Cells of Scutellvm of it IS shown in fag. 0, p. 49d. ihe em- 
Barley (e in Fig. 6) x 250. bryo is separated from the endosperm 
a '^t m J2^Z^t^ by a peculiar shield-like expansion, 
the scutellum, which is covered by a 
delicate coat. The microscope shows this coat to be formed of 
a layer of cells which are columnar in shape (fig. 16), their 
1 A molecule of any substance is the smallest quantity wliich is able to 
take part in or result from a chemical change, or to exist in a free state. 
Molecules are made up of atoms. The molecule of starch is thought to be 
composed of six parts or atoms of carbon (C), ten atoms of hydrogen (H), 
and five atoms of oxygen (O), or of some multiple of this quantity. This is 
represented by the formula C,jH 10 O 5 . The molecule of water is made up of two 
atoms of hydrogen and one of oxygen, and is expressed as H.,0. The change 
effected by the ferment— viz., the transformation of starch into sugar — may lie 
expressed shortly by the equation Cyj 1(l O. + H,0 = C 6 H 12 0 6 - Probably th.e de- 
composition is not so simple as tins. 
