“In South America three classes of facts were brought strongly before my mind. Firstly, the manner in which closely allied species replace species in going southward. Secondly, the close affinity of the species inhabiting the islands near South America to those proper to the continent. This struck me profoundly, especially the difference of the species in the adjoining islets in the Galapagos Archipelago. Thirdly, the relation of the living Edentata and Rodentia to the extinct species. I shall never forget my astonishment when I dug out a gigantic piece of armour like that of the living armadillo.

“Reflecting on these facts, and collecting analogous ones, it seemed to me probable that allied species were descended from a common ancestor. But during several years I could not conceive how each form could have been modified so as to become admirably adapted to its place in nature. I began, therefore, to study domesticated animals and cultivated plants, and after a time perceived that man’s power of selecting and breeding from certain individuals was the most powerful of all means in the production of new races. Having attended to the habits of animals and their relations to the surrounding conditions, I was able to realise the severe struggle for existence to which all organisms are subjected, and my geological observations had allowed me to appreciate to a certain extent the duration of past geological periods. Therefore, when I happened to read Malthus on population, the idea of natural selection flashed on me. Of all minor points, the last which I appreciated was the importance and cause of the principle of divergence.”

This is all very naïve, and accords perfectly with the introductory paragraphs of the “Origin of Species;” it gives us the same picture of a solitary thinker, a poor, lonely, friendless student of nature, who had never so much as heard of Buffon, Erasmus Darwin, or Lamarck. Unfortunately, however, we cannot forget the description of the influences which, according to Mr. Grant Allen, did in reality surround Mr. Darwin’s youth, and certainly they are more what we should have expected than those suggested rather than expressly stated by Mr. Darwin. “Everywhere around him,” says Mr. Allen, [174a] “in his childhood and youth these great but formless” (why “formless”?) “evolutionary ideas were brewing and fermenting. The scientific society of his elders and of the contemporaries among whom he grew up was permeated with the leaven of Laplace and Lamarck, of Hutton and of Herschel. Inquiry was especially everywhere rife as to the origin and nature of specific distinctions among plants and animals. Those who believed in the doctrine of Buffon and of the ‘Zoonomia,’ and those who disbelieved in it, alike, were profoundly interested and agitated in soul by the far-reaching implications of that fundamental problem. On every side evolutionism, in its crude form.” (I suppose Mr. Allen could not help saying “in its crude form,” but descent with modification in 1809 meant, to all intents and purposes, and was understood to mean, what it means now, or ought to mean, to most people.) “The universal stir,” says Mr. Allen on the following page, “and deep prying into evolutionary questions which everywhere existed among scientific men in his early days was naturally communicated to a lad born of a scientific family and inheriting directly in blood and bone the biological tastes and tendencies of Erasmus Darwin.”

I confess to thinking that Mr. Allen’s account of the influences which surrounded Mr. Darwin’s youth, if tainted with picturesqueness, is still substantially correct. On an earlier page he had written:—“It is impossible to take up any scientific memoirs or treatises of the first half of our own century without seeing at a glance how every mind of high original scientific importance was permeated and disturbed by the fundamental questions aroused, but not fully answered, by Buffon, Lamarck, and Erasmus Darwin. In Lyell’s letters, and in Agassiz’s lectures, in the ‘Botanic Journal’ and in the ‘Philosophical Transactions,’ in treatises on Madeira beetles and the Australian flora, we find everywhere the thoughts of men profoundly influenced in a thousand directions by this universal evolutionary solvent and leaven.

“And while the world of thought was thus seething and moving restlessly before the wave of ideas set in motion by these various independent philosophers, another group of causes in another field was rendering smooth the path beforehand for the future champion of the amended evolutionism. Geology on the one hand and astronomy on the other were making men’s minds gradually familiar with the conception of slow natural development, as opposed to immediate and miraculous creation.

. . .

“The influence of these novel conceptions upon the growth and spread of evolutionary ideas was far-reaching and twofold. In the first place, the discovery of a definite succession of nearly related organic forms following one another with evident closeness through the various ages, inevitably suggested to every inquiring observer the possibility of their direct descent one from the other. In the second place, the discovery that geological formations were not really separated each from its predecessor by violent revolutions, but were the result of gradual and ordinary changes, discredited the old idea of frequent fresh creations after each catastrophe, and familiarised the minds of men of science with the alternative notion of slow and natural evolutionary processes. The past was seen in effect to be the parent of the present; the present was recognised as the child of the past.”

This is certainly not Mr. Darwin’s own account of the matter. Probably the truth will lie somewhere between the two extreme views: and on the one hand, the world of thought was not seething quite so badly as Mr. Allen represents it, while on the other, though “three classes of fact,” &c., were undoubtedly “brought strongly before” Mr. Darwin’s “mind in South America,” yet some of them had perhaps already been brought before it at an earlier time, which he did not happen to remember at the moment of writing his letter to Professor Haeckel and the opening paragraph of the “Origin of Species.”

Chapter XIV
Darwin and Descent with Modification (continued)

I have said enough to show that Mr. Darwin claimed I to have been the originator of the theory of descent with modification as distinctly as any writer usually claims any theory; but it will probably save the reader trouble in the end if I bring together a good many, though not, probably, all (for I much disliked the task, and discharged it perfunctorily), of the passages in the “Origin of Species” in which the theory of descent with modification in its widest sense is claimed expressly or by implication. I shall quote from the original edition, which, it should be remembered, consisted of the very unusually large number of four thousand copies, and from which no important deviation was made either by addition or otherwise until a second edition of two thousand further copies had been sold; the “Historical Sketch,” &c., being first given with the third edition. The italics, which I have employed so as to catch the reader’s eye, are mine, not Mr. Darwin’s. Mr. Darwin writes:—