The seventh essay, “The Coming of Age of ‘The Origin of Species,’” was written in 1880. His complete confidence in evolution, as shown in this essay, may be contrasted with his cautious statements about natural selection. He boldly affirms evolution to be the fundamental doctrine of the “Origin of Species,” while natural selection is, I believe, neither mentioned nor even alluded to. On this great occasion he thus emphasised the immense debt we owe to Darwin in that he was the first to produce adequate evidence in favour of the ancient doctrine of evolution, a benefit quite distinct from that which he conferred in the theory of natural selection (see pp. 100–102). The following are among the most confident statements about evolution to be found in this essay. Speaking of the “Origin,” he says (p. 229):-- “... the general doctrine of evolution, to one side of which it gives expression, obtains, in the phenomena of biology, a firm base of operations whence it may conduct its conquest of the whole realm of nature.” And again, on page 332:-- “The fundamental doctrine of the ‘Origin of Species,’ as of all forms of the theory of evolution applied to biology, is ‘that the innumerable species, genera, and families of organic beings with which the world is peopled have all descended, each within its own class or group, from common parents, and have all been modified in the course of descent.’” Furthermore, on page 242 we read:-- “I venture to repeat what I have said before, that so far as the animal world is concerned, evolution is no longer a speculation, but a statement of historical fact. It takes its place alongside of those accepted truths which must be reckoned with by philosophers of all schools.” And on the same page he quotes with approval the statement by M. Filhol of the results to which he had been led by his palæontological investigations:-- “Under the influence of natural conditions of which we have no exact knowledge, though traces of them are discoverable, species have been modified in a thousand ways: species have arisen which, becoming fixed, have thus produced a corresponding number of secondary species.” Similarly, in the Obituary notice in _Nature_ (1882), Huxley speaks of the secure position in which Darwin had placed the doctrine of evolution as his great achievement. The following eloquent passage occurs on page 247 of “Darwiniana”:-- “None have fought better, and none have been more fortunate, than Charles Darwin. He found a great truth trodden underfoot, reviled by bigots, and ridiculed by all the world; he lived long enough to see it, chiefly by his own efforts, irrefragibly established in science,...”