WCP4867

[1]

5, Westbourne Grove Terrace, w.

Tuesday, May 24th.¹ [1864]²

My dear Sir,

Many thanks for your note & kind criticisms on my little paper³. I mentioned the "Mound" crania, because I understood that they were undoubtedly of of [sic] the American Indian type. I sh[oul]^d however have said "infancy of the Indian race" instead of "human race".

With regard to the probable antiquity of man I will say a few words. First, you will see I argue rather for the possibility than for the necessity of man’s having existed in Miocene⁴ [2] times & I still maintain this possibility & new probability, for the following reasons. The question of time cannot be judged of positively but only comparatively. We cannot say à priori that ten millions or a thousand millions of years would be required for any given modification in man. We must judge only by analogy, & by a comparison with the rate of change of other highly organized animals. Now several existing genera lived in the Miocene age, and also Anthropoid apes allied to Hylobates. But man, even by Huxley⁵, is classed as a distinct family. The origin of that [3] family ^{that is its common origin with other families of the primates} must therefore date back from a far earlier period than the Miocene.

Now the greater part of the family difference is manifested in the head & cranium. A being almost exactly like man in the rest of the skeleton but with a cranium as little developed as that of a Chimpanzee would certainly not form a distinct family, only a distinct genus of Primates.

My argument therefore is, that this great cranial difference has been slowly developing, while the rest of the skeleton has remained nearly stationary; and while the Miocene Dryopithecus has been modified into the modern Gorilla, — speechless & ape-brained man [4] (but still man) has been developed into existing great-brained speech-forming man.

The majority of Pliocene mammals on the other hand are I believe of existing genera; and as my whole argument is to show how man has undergone a more than generic change in brain & cranium, while the rest of his body has hardly changed specifically, I cannot consistently admit that all this change has been brought about in a less period than has sufficed to change most other mammals generically, — except by assuming that in his case the change has been more rapid, — which may indeed have been so, but which we have no evidence yet to prove. I conceive therefore that the immensity of time measured in years does not touch the argument.

My paper was written far too hastily & too briefly, to explain the subject with clearness, but I hope these few remarks may give my ideas in the point you have specifically referred to.

Very truly yours | Alfred R. Wallace [signature]