OF THE RELATION OF VEGETATION TO SEASONS. 
265 
the operation practicable; but if we wait till the spring, the sponge- 
lets which form during winter are likely to be destroyed, and many 
causes may call the already turgid plant into growth, before the roots 
have had time to form new spongelets. 
Ci The seasons of growth and repose are so essential to vegetation, 
that, as is familiar to all gardeners, it is scarcely possible to prevent 
plants preparing themselves for their annual changes, whatever arti¬ 
ficial means may be employed to maintain them in a uniform atmos¬ 
phere, and to protect them from those causes which usually bring about 
repose; and this is certain, that if we can succeed in preventing the 
cessation of growth, the plants which are the subject of the experiment 
uniformly, in the end, fall victims to the forced and unnatural condition 
in which they are maintained. 
“ If annual changes in their condition be requisite to the well-being 
of plants, so in like manner are the diurnal changes of light and dark¬ 
ness. If plants were kept incessantly growing in light, they would be 
perpetually decomposing carbonic acid, and would, in consequence, 
become so stunted that there would be no such thing as a tree, as is 
actually the case in the polar regions. If, on the contrary, they grow 
in constant darkness, their tissue becomes excessively lengthened and 
weak, no decomposition of carbonic acid takes place, none of the parts 
acquire solidity or vigour, and finally perish. But under natural 
circumstances, plants which in the day become exhausted by the de¬ 
composition of carbonic acid, and by the emptying of their tissue by 
evaporation, repair their forces at night by inhaling oxygen copiously, 
and so forming a new supply of carbonic acid, and by absorbing 
moisture from the earth and air, without the loss of any portion 
of it. 
“ Such being the case, we must conclude that plants grow chiefly 
by day and this is conformable to the few observations that have 
been made upon the subject. Meyer found the stem of a Belladonna 
lily, and plants of wheat and barley, grow by day nearly twice as fast 
as at night; and Mulder states that he has arrived at a similar result 
in watching the development of other plants.”— Botany, Part IV., 
p. 98. 
[As we have had, and shall have, frequent opportunities of descant¬ 
ing on the growth of plants for the instruction or amusement of our 
readers, we think it right, as very different opinions are held thereon, 
to glean from every respectable quarter the ideas entertained or pro¬ 
mulgated by each, in order that steady and rational views may be 
acquired of vegetable phenomena, which may be applicable to practical 
purposes.]—E d. 
VOL. V. — NO. LXI. 
M M 
