MULTIPLICATION, 83 
ingredients necessary for the nutrition of the young 
potato plants. The “eyes” of the potato are really 
buds, as any one may see for himself who will examine 
the “chits” of a sprouting potato.. These latter bear 
the same relation to the parent tuber that the shoots 
which spring from the old ‘‘stools” in a coppice or from 
a pollard willow do to the trunk. The presence of these 
tubers indicates that, under natural circumstances, the 
plant requires a long period of rest. To this end food is 
stored in the tuber, and active growth ceases for a time, 
until again excited by heat and moisture. It may be 
inferred from this that continuous growth, were it possi- 
ble, would be injurious because the climatal conditions . 
are unsuited for it, as, indeed, may be witnessed in the 
way in which the haulms of the early potatoes are injured 
by spring frost. 
Fertilization,—In the case of plants grown for their 
fruit or seed, as in the case of wheat and cereals generally, 
much attention has naturally to be paid to the conditions 
which favor sexual multiplication. 
The morphological characters of the plants undergo a 
change. In general terms, it may be said that the growth 
of the stem is arrested, and the growth and mode of de- 
velopment of the leaves not only arrested, but more or 
less profoundly modified, so as to form the parts of the 
flower. All parts of the flower are constructed on the 
same original plan as leaves, but they gradually assume a 
very different appearance in the course of their develop- 
ment to fit them for their work of aiding fertilization. 
It is not necessary in this place to enter into details as to 
the floral construction, which varies in different plants ; 
the important points in relation to our present subject 
are the stamens and the pistils and their contents. 
Within the green scales which constitute the flower of 
