82 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 aflFect 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 

 difficult 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 



