10 VAKIATION 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, and 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 seem 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 



