10 
VARIATION 
Chap. I. 
Such buds can be propagated by grafting, &c., and 
sometimes by seed. These sports ” are extremely 
rare under nature, but far from rare under cultivation ; 
and in this case we see that the treatment of the parent 
has affected a bud or offset, and not the ovules or pollen. 
But it is the opinion of most physiologists that there is no 
essential difference between a bud and an ovule in their 
earliest stages of formation; so that, in fact, sports ” 
support my view, that variability may be largely attri¬ 
buted to the ovules or pollen, or to both, having been 
affected by the treatment of the parent prior to the act 
of conception. These cases anyhow show that variation 
is not necessarily connected, as some authors have sup¬ 
posed, with the act of generation. 
Seedlings from the same fruit, and the young of the 
same litter, sometimes differ considerably from each 
other, though both the young and the parents, as Muller 
has remarked, have apparently been exposed to exactly 
the same conditions of life ; and this shows how unim¬ 
portant the direct effects of the conditions of life are 
in comparison with the laws of reproduction, of growth, 
and of inheritance ; for had the action of the conditions 
been direct, if any of the young had varied, all would 
probably have varied in the same manner. To judge how 
much, in the case of any variation, we should attribute 
to the direct action of heat, moisture, light, food, &c., 
is most difficult: my impression is, that with animals 
such agencies have produced very little direct effect, 
though apparently more in the case of plants. Under 
this point of view, Mr. Buckman’s recent experiments 
on plants are extremely valuable. When all or nearly 
all the individuals exposed to certain conditions are 
affected in the same way, the change at first appears to 
be directly due to such conditions ; but in some cases it 
can be shown that quite opposite conditions produce 
