Lyell, up to that time a pillar of the anti-transmutationists (who regarded him, ever afterwards, as Pallas Athene may have looked at Dian, after the Endymion affair), declared himself a Darwinian, though not without putting in a serious caveat.  Nevertheless, he was a tower of strength, and his courageous stand for truth as against consistency did him infinite honour. (T.H.  Huxley in “Life of Darwin” volume 2 page 231.)

[To Sir Charles Lyell.]

June 25, 1859.

My dear Sir Charles,

I have endeavoured to meet your objections in the enclosed.

Ever yours, very truly,

T.H.  Huxley.

The fixity and definite limitation of species, genera, and larger groups appear to me to be perfectly consistent with the theory of transmutation.  In other words, I think transmutation may take place without transition.

Suppose that external conditions acting on species A give rise to a new species, B; the difference between the two species is a certain definable amount which may be called A-B.  Now I know of no evidence to show that the interval between the two species must necessarily be bridged over by a series of forms, each of which shall occupy, as it occurs, a fraction of the distance between A and B. On the contrary, in the history of the Ancon sheep, and of the six-fingered Maltese family, given by Reaumur, it appears that the new form appeared at once in full perfection.

I may illustrate what I mean by a chemical example.  In an organic compound, having a precise and definite composition, you may effect all sorts of transmutations by substituting an atom of one element for an atom of another element.  You may in this way produce a vast series of modifications—­but each modification is definite in its composition, and there are no transitional or intermediate steps between one definite compound and another.  I have a sort of notion that similar laws of definite combination rule over the modifications of organic bodies, and that in passing from species to species “Natura fecit saltum.”

All my studies lead me to believe more and more in the absence of any real transitions between natural groups, great and small—­but with what we know of the physiology of conditions [?] this opinion seems to me to be quite consistent with transmutation.

When I say that no evidence, or hardly any, would justify one in believing in the view of a new species of Elephant, e.g. out of the earth, I mean that such an occurrence would be so diametrically contrary to all experience, so opposed to those beliefs which are the most constantly verified by experience, that one would be justified in believing either that one’s senses were deluded, or that one had not really got to the bottom of the phenomenon.  Of course, if one could vary the conditions, if one could take a little silex, and by a little hocus-pocus a la crosse, galvanise a baby out of it as often as one pleased, all the philosopher could do would be to hold up his hands and cry, “God is great.”  But short of evidence of this kind, I don’t mean to believe anything of the kind.