TRANSMUTABLE. 227 



bull-dogs, at six days old, and found that they 

 had not nearly "acquired their full amount of 

 proportional difference." 



The same experiment with the foals and mothers 

 of the cart-horse, and racer, gave similar results. 

 So with all the race of domestic pigeons, and 

 their proportional differences in the specified several 

 points of beak, width of mouth, length of eyelid, 

 size of foot, and length of leg, were very much 

 less when compared with the blue-rock, than in 

 the full-grown birds, with one remarkable excep- 

 tion, namely, the short-faced tumbler. 



Alluding to the above measurements, Mr. Dar- 

 win remarks, u Fanciers select their horses, dogs, 

 and pigeons, for breeding, when they are nearly 

 grown up ; they are indifferent whether the desired 

 qualities and structures have been acquired earlier 

 or later in life, if the full-grown animal possesses 

 them. And the cases just given, more especially 

 that of pigeons, seem to shew that the charac- 

 teristic differences, which give value to each 

 breed, and which have been accumulated by man's 

 selection, have not generally first appeared at an 

 early period of life, and have been inherited by 

 the offspring at a corresponding not early period" 



So that because the pigeon, twelve hours old, 

 an imperfect organism, with one part, according 

 to the laws of development, more advanced than 

 another; because this half-formed pigeon does not, 

 at twelve hours, shew the proportions of difference 

 in structure which is exhibited by the full-grown 

 bird, and the presumed original stock, the blue- 



