Mention has been made of the instant support he was able to lend the Origin in the Times review of the book, and the extension of its doctrines in regard to man.  Even before the book appeared, however, he began to act as what Darwin laughingly called his “general agent.”  His address on “Persistent Types” (June, 1859) aimed at clearing up in advance one of the obvious objections raised against acceptance of the doctrine of Evolution—­namely, how is it that, if evolution is ever progressive, progress is not universal?  How is it that all forms do not necessarily advance, and that simple organisms still exist?  As it happened, Darwin did not discuss this point when he first put the Origin together, and speedily came to regard this as the most serious omission in the book.

Great, then, was the debt of all science to Darwin.  And not of science only.  The fight for freedom of thought and speech in science, into which Huxley especially threw himself, was the more successful because the immediate cause he upheld was so overwhelmingly strong in reason and demonstration; and, the supreme curb upon thought being once broken, a wider freedom was gained.

For Darwin, therefore, Huxley had the reverence due to one who had forged a new and mighty weapon in the war for plain truth.  But, while he could not but uphold a theory so much in accord with his own knowledge and so fruitful in its promise of new knowledge, whether the author of it were his friend or not, admiration and affection for a man of such utter sincerity, such selfless respect for truth, and warm personality, led him, when those views were stupidly or maliciously attacked, to take more trouble in his defence and support, and to strike out much harder at his adversary than he would otherwise have done.  Darwin’s friends were well assured that the scanty time which his health allowed for work was far too precious to be wasted in controversy; for his own sake and for the sake of the calm atmosphere in which a great theory should be worked out, they thought that the battling on a lower plane should be left to them.  “You ought to be like one of the blessed gods of Elysium, and let the inferior deities do battle with the infernal powers.”  “If I say a savage thing,” Huxley told him, “it is only ‘pretty Fanny’s way’; but if you do, it is not likely to be forgotten.”  Hence a dash of personal pleasure was infused into the duty of upholding and defending the bringer of new light.