136 DARWINISM STATED BY DARWIN HIMSELF. 



into a horse, hardly any light is thrown hy the belief in 

 abrupt modifications on the deficiency of connecting links 

 in our geological formations. But against the belief in 

 such abrupt changes embryology enters a strong protest. 

 It is notorious that the wings of birds and bats, and the 

 legs of horses or other quadrupeds, are undistinguishable 

 at an early embryonic period, and that they become differ- 

 entiated by insensibly fine steps. Embryological resem- 

 blances of all kinds can be accounted for, as we shall 

 hereafter see, by the progenitors of our existing species 

 having varied after early youth, and having transmitted 

 their newly acquired characters to their offspring at a 

 corresponding age. The embryo is thus left almost un- 

 affected, and serves as a record of the past condition of 

 the species. Hence it is that existing species during the 

 early stages of their development so often resemble an- 

 cient and extinct forms belonging to the same class. On 

 this view of the meaning of embryological resemblances, 

 and indeed on any view, it is incredible that an animal 

 should have undergone such momentous and abrupt trans- 

 formations as those above indicated, and yet should not 

 bear even a trace in its embryonic condition of any sud- 

 den modification, every detail in its structure being de- 

 veloped by insensibly fine steps. 



He who believes that some ancient form was trans- 

 formed suddenly through an internal force or tendency 

 into, for instance, one furnished with wings, will be al- 

 most compelled to assume, in opposition to all analogy, 

 that many individuals varied simultaneously. It can not 

 be denied that such abrupt and great changes of struct- 

 ure are widely different from those which most species 

 apparently have undergone. He will further be com- 

 pelled to believe that many structures beautifully adapted 

 to all the other parts of the same creature and to the 



