Darwin's Artificial and Natural Selection 123 
shows that if a single individual were born, which varied in 
some manner, giving it twice as good a chance of. life as that 
of the other individuals, yet the chances would be strongly 
against its survival. Supposing it to survive and to breed, 
and that half its young inherited the favourable variation ; 
still, as the reviewer goes on to show, the young would have 
only a slightly better chance of surviving and breeding; and 
this chance would go on decreasing in the succeeding genera- 
tions. The justice of these remarks cannot, I think, be dis- 
puted. If, for instance, a bird of some kind could procure 
its food more easily by having its beak curved, and if one 
were born with its beak strongly curved, and which conse- 
quently flourished, nevertheless there would be a very poor 
chance of this one individual perpetuating its kind to the ex- 
clusion of the common form; but there can hardly be a 
doubt, judging by what we see taking place under domestica- 
tion, that this result would follow from the preservation dur- 
ing many generations of a large number of individuals with 
more or less strongly curved beaks, and from the destruction 
of a still larger number with the straightest beaks.” 
There then follows what, I believe, is one of the most sig- 
nificant admissions in the “Origin of Species” : — 
“It should not, however, be overlooked that certain rather 
strongly marked variations, which no one would rank as mere 
individual differences, frequently recur owing to a similar 
organization being similarly acted on — of which fact numer- 
ous instances could be given with our domestic productions. 
In such cases, if the varying individual did not actually trans- 
mit to its offspring its newly acquired character, it would 
undoubtedly transmit to them, as long as the existing condi- 
tions remained the same, a still stronger tendency to vary in 
the same manner. There can also be little doubt that the 
tendency to vary in the same manner has often been so 
strong that all the individuals of the same species have been 
similarly modified without the aid of any form of selection. 
