Darwin's Artificial and Natural Selection 99 
comparison with the leaves and flowers of the same set of 
varieties. See how different the leaves of the cabbage are, 
and how extremely alike the flowers; how unlike the flowers 
of the heartsease are, and how alike the leaves; how much 
the fruit of the different kinds of gooseberries differ in size, 
color, shape, and hairiness, and yet the flowers present very 
slight differences. It is not that the varieties which differ 
largely in some one point do not differ at all in other points; 
this is hardly ever, —I speak after careful observation,— per- 
haps never, the case. The law of correlated variation, the 
importance of which should never be overlooked, will insure 
some differences; but, as a general rule, it cannot be doubted 
that the continued selection of slight variations, either in the 
leaves, the flowers, or the fruit, will produce races differing 
from each other chiefly in these characters.’ 
Exception may perhaps be taken to the concluding sen- 
tence, for, interesting as the facts here recorded certainly 
are, it does not necessarily follow that all domestic products 
have arisen “by the continued selection of slight variations,” 
however probable the conclusion may appear. Darwin also 
believes that a process of “unconscious selection” has given 
even more important “results than methodical selection.” By 
unconscious selection is meant the outcome of “every one 
trying to possess and breed from best individual animals.” 
“Thus a man who intends keeping pointers naturally tries 
to get as good dogs as he can, and afterwards breeds from 
his own best dogs, but he has no wish, or expectation of per- 
manently altering the breed. Nevertheless we may infer 
that this process, continued during centuries, would improve 
and modify any breed... . There is reason to believe that 
the King Charles spaniel has been unconsciously modified 
‘to a large extent since the time of that monarch.” 
The enormous length of time required to produce new 
species by the selection of fluctuating variations is every- 
where admitted by Darwin ; nowhere perhaps more strikingly 
