a friendship which, I am happy to think, has known no interruption.  Many and prolonged were the battles we fought on this topic.  But even my friend’s rare dialectic skill and copiousness of apt illustration could not drive me from my agnostic position.  I took my stand upon two grounds:—­Firstly, that up to that time, the evidence in favour of transmutation was wholly insufficient; and secondly, that no suggestion respecting the causes of transmutation assumed, which had been made, was in any way adequate to explain the phenomena.  Looking back at the state of knowledge at that time, I really do not see that any other conclusion was justifiable.

In those days I had never even heard of Treviranus’ “Biologie.”  However, I had studied Lamarck attentively and I had read the “Vestiges” with due care; but neither of them afforded me any good ground for changing my negative and critical attitude.  As for the “Vestiges,” I confess that the book simply irritated me by the prodigious ignorance and thoroughly unscientific habit of mind manifested by the writer.  If it had any influence on me at all, it set me against Evolution; and the only review I ever have qualms of conscience about, on the ground of needless savagery, is one I wrote on the “Vestiges” while under that influence...

But, by a curious irony of fate, the same influence which led me to put as little faith in modern speculations on this subject as in the venerable traditions recorded in the first two chapters of Genesis, was perhaps more potent than any other in keeping alive a sort of pious conviction that Evolution, after all, would turn out true.  I have recently read afresh the first edition of the “Principles of Geology”; and when I consider that this remarkable book had been nearly thirty years in everybody’s hands, and that it brings home to any reader of ordinary intelligence a great principle and a great fact,—­the principle that the past must be explained by the present, unless good cause be shown to the contrary; and the fact that so far as our knowledge of the past history of life on our globe goes, no such cause can be shown—­I cannot but believe that Lyell, for others, as for myself, was the chief agent in smoothing the road for Darwin.  For consistent uniformitarianism postulates Evolution as much in the organic as in the inorganic world.  The origin of a new species by other than ordinary agencies would be a vastly greater “catastrophe” than any of those which Lyell successfully eliminated from sober geological speculation.

Thus, looking back into the past, it seems to me that my own position of critical expectancy was just and reasonable, and must have been taken up, on the same grounds, by many other persons.  If Agassiz told me that the forms of life which have successively tenanted the globe were the incarnations of successive thoughts of the Deity; and that he had wiped out one set of these embodiments by an appalling geological catastrophe as soon as His ideas took a more advanced