612 THE PHYSIOLOGY OF SOWING SEEDS. 
plant from a vigorous stock. Ifthe vital energies 
of that stock have been by any means impaired, 
the descendant plant will participate in the loss. 
This fact is obvious in the destruction of the 
leaves of plants by insects, which so weakens the 
buds, which the leaves have to maintain, that the 
shoots next season are weak and sickly; nay, 
in some instances the whole vitality of the plant 
is thereby destroyed and it perishes. Weakening 
the bud ever weakens the future shoot, be the 
conditions externally as favourable as they may. 
Allowing seed potatoes to sprit, and then pulling 
off the sprits, is an infringement of this law. The 
vital energy of the bud which succeeds is lessened, 
and a less vigorous shoot is the consequence, 
and not only so, but less vitality is communicated 
to the buds of the tubers, which are to continue 
the individuals of the species, or variety, for the 
succeeding season. So that even by a perseve- 
rance in this infringement of a natural law, we 
may, whether ignorantly or otherwise is of no 
consequence, ultimately reduce the vital energy 
of the buds so low, that it cannot overcome the 
resistances which surround it ; and over planted | 
tubers, or sets of potatoes, may fail to germinate 
entirely ; as in the instance of plants perishing 
by the reduction in the vital energy of the buds 
