)8s9-j LYELL'S CRITICISMS. 



so many whole classes of facts, which, if I am in my senses, it 

 seems to explain. As far as I understand your remarks and 

 illustrations, you doubt the possibility of gradations of intel- 

 lectual powers. Now, it seems to me, looking to existing 

 animals alone, that we have a very fine gradation in the intel- 

 lectual powers of the Vertebrata, with one rather wide gap (not 

 half so wide as in many cases of corporeal structure), between 

 say a Hottentot and an Ourang, even if civilised as much 

 mentally as the dog has been from the wolf. I suppose that 

 you do not doubt that the intellectual powers are as important 

 for the welfare of each being as corporeal structure ; if so, I 

 can see no difficulty in the most intellectual individuals of a 

 species being continually selected ; and the intellect of the 

 new species thus improved, aided probably by effects of 

 inherited mental exercise. I look at this process as now 

 going on with the races of man ; the less intellectual races 

 being exterminated. But there is not space to discuss this 

 point. If I understand you, the turning-point in our differ- 

 ence must be, that you think it impossible that the intellec- 

 tual powers of a species should be much improved by the 

 continued natural selection of the most intellectual individ- 

 uals. To show how minds graduate, just reflect how impos- 

 sible every one has yet found it, to define the difference in 

 mind of man and the lower animals ; the latter seem to have 

 the very same attributes in a much lower stage of perfectio'n 

 than the lowest savage. I would give absolutely nothing for 

 the theory of Natural Selection, if it requires miraculous 

 additions at any one stage of descent. I think Embryology, 

 Homology, Classification, &c., &c., show us that all verte- 

 brata have descended from one parent ; how that parent 

 appeared we know not. If you admit in ever so little a 

 degree, the explanation which I have given of Embryology, 

 Homology and Classification, you will find it difficult to say : 

 thus far the explanation holds good, but no further ; here we 

 must call in " the addition of new creative forces." I think 

 you will be driven to reject all or admit all : I fear by your 

 letter it will be the former alternative ; and in that case I 



