PERPETUATION OF LIVING BEINGS. Ill 



and legs, just like those of the Ass, the Quagga, and 

 the Zebra. Now, if we interpret the theory of recur- 

 rence as applied to this case, might it not be said that 

 here was a case of a variation exhibiting the characters 

 and conditions of an animal occupying something like 

 an intermediate position between the Horse, the Ass, 

 the Quagga, and the Zebra, and from which these had 

 been developed ? In the same way with regard even 

 to Man. Every anatomist will tell you that there is 

 nothing commoner, in dissecting the human body, than 

 to meet with what are called muscular variations — that 

 is, if you dissect two bodies very carefully, you will 

 probably find that the modes of attachment and inser- 

 tion of the muscles are not exactly the same in both, 

 there being great peculiarities in the mode in which 

 the muscles are arranged ; and it is very singular, that 

 in some dissections of the human body you will come 

 upon arrangements of the muscles very similar indeed 

 to the same parts in the Apes. Is the conclusion in 

 that case to be, that this is like the -black bars in the 

 case of the Pigeon, and that it indicates a recurrence 

 to the primitive type from which the animals have been 

 probably developed? Truly, I think that the oppo- 

 nents of modification and variation had better leave 

 the argument of recurrence alone, or it may prove alto- 

 gether too strong for them. 



To sum up, — the evidence as far as we have gone 

 is against the argument as to any limit to divergences, 

 so far as structure is concerned ; and in favour of a 

 physiological limitation. By selective breeding we 

 can produce structural divergences as great as those 

 of species, but we cannot produce equal physiological 

 divergences. For the present I leave the question 

 there. 



