Professor Huxley considers that just as by Darwin’s practical experience of physical geography, geology, etc., on the _Beagle_, “he knew of his own knowledge the way in which the raw materials of these branches of science are acquired, and was, therefore, a most competent judge of the speculative strain they would bear,” so his Cirripede work fitted him for his subsequent speculations upon the deepest biological problems. “It was a piece of critical self-discipline, the effect of which manifested itself in everything your father wrote afterwards, and saved him from endless errors of detail” (Letter to F. Darwin, “Life and Letters”). The history of Darwin’s career has often been used as an argument against those who, not having passed through a similar training as regards systematic zoological work, have ventured to concern themselves with the problems of evolution. Professor Meldola has recently treated of this subject in his interesting presidential address to the Entomological Society (1896). He says:-- “It used formerly to be asserted that he only is worthy of attention who has done systematic, _i.e._ taxonomic, work. I do not know whether this view is still entertained by entomologists; if so, I feel bound to express my dissent. It has been pointed out that the great theorisers have all done such work--that Darwin monographed the Cirripedia, and Huxley the oceanic Hydrozoa, and it has been said that Wallace’s and Bates’s contributions in this field have been their biological salvation. I yield to nobody in my recognition of the value and importance of taxonomic work, but the possibilities of biological investigation have developed to such an extent since Darwin’s time that I do not think this position can any longer be seriously maintained. It must be borne in mind that the illustrious author of the ‘Origin of Species’ had none of the opportunities for systematic training in biology which any student can now avail himself of. To him the monographing of the Cirripedia was, as Huxley states in a communication to Francis Darwin, ‘a piece of critical self-discipline,’ and there can be no reasonable doubt that this value of systematic work will be generally conceded. That this kind of work gives the sole right to speculate at the present time is, however, quite another point.” Meldola then goes on to argue that the systematic work of those who know nothing of the living state of the species they are describing does not specially fit them for theorising, and he concludes by quoting the following passage from a letter recently received from A. R. Wallace:--