42 ADAM SEDGWICK. 
counter to the great authority of Darwin. In the chapter 
from which the above quotation was taken he gives many facts 
and arguments in favour of the view that slight variations 
generally appear at a not very early period of life, and are 
inherited at a corresponding not early period. He admits that 
larger variations—monstrosities—do affect the embryo at a 
very early period, but he thinks that slight variations do not. 
Without considering the difficult question as to where the line 
should be drawn between a slight variation and a monstrosity, 
I may merely point out that Darwin’s evidence is largely based 
upon the experience of breeders that it is impossible to tell 
until some time after birth what will be the merits or demerits 
of their young animals. In mitigation of the force of this fact 
it must be-remembered that a successful breeder is a highly 
skilled man—that he possesses powers of observation greater 
than the ordinary—that his success depends upon his ability 
to see points which escape the eye of other people. If the 
points for which the mature animal is selected are thus 
ditficult of observation, can we wonder if it is beyond the 
power of man to see them when the animal is immature, and 
the relative sizes of the parts of the animal, and its whole 
appearance, are so different? In support of this way of looking 
at the matter I would urge that when the variation is large 
and of a nature to be easily observed, it can—in a great 
many instances at any rate—be detected all through develop- 
ment. 
The evidence is of this kind :—(1) Organs which we know 
have only recently disappeared are not developed at all in the 
embryo. For instance, the teeth of birds, the fore-limbs of 
snakes, reduced toes of bird’s foot (and probably of horse’s 
foot), the reduced fingers of a bird’s hand. These are instances 
which readily occur; I have no doubt that many others might 
be quoted by anyone giving attention to the matter. (2) Organs 
which have (presumably) recently become reduced or enlarged 
in the adult, are also reduced or enlarged in the embryo. 
Many examples of this might be given, and it is a most im- 
portant point as showing the manner in which variations have 
