CHAPTER IV.

F no other record of Darwin's twenty-two years (1837

IF

59) of life and thought after his return to England remained than the papers and books he published during that period, we should find enough to place him on a level with the most gifted biologists and geologists of his age. But all that time he was occupied with thoughts, researches, and experiments, of which the world at large perceived no fruits. Few persons suspected that a tremendous revolution in scientific thought was in preparation at the quiet country home at Down.

species of animals and plants were being described by naturalists at an alarming rate. The bulk of knowledge of specific characters and the necessity of specialisation bade fair to make every species-monger a dry and narrow pedant; and the pedants quarrelled about the characters and limits of their species.

In the later years of this period some rays of improvement shone out. To end the reign of Owen's misleading types and imaginary archetypes, there arose a wielder of two potent words, "morphology" and "biology," the sciences of form and of life, who showed that differences of adult form grew out of likeness and simplicity in the

young; and that the life of plants and animals was one science, their study one discipline. What Huxley had begun to proclaim from the housetop, Darwin was meditating in secret; and much more. Let us see how he states the case in the famous modest opening of the "Origin of Species" (1859): "When on board H. M. S. Beagle, as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species-that mystery of mysteries, as it has been called by one of our greatest philosophers. On my return home, it occurred to me, in 1837, that something might perhaps be made out on this question by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it. After five years' work I allowed myself to speculate on the subject, and drew up some short notes; these I enlarged in 1844 into a sketch of the conclusions, which then seemed to me probable : from that period to the present day I have steadily pursued the same object. I hope that I may be excused for entering on these personal details, as I give them to show that I have not been hasty in coming to a decision." We learn also, independently, from the "Expression of the Emotions" (p. 19), that Darwin as early as 1838 was inclined to believe in the principle of evolution, or the derivation of species from other and lower forms.

It is somewhat difficult to decide precisely what Darwin owed to his predecessors who believed in the mutability of species and doubted their separate creation;

this is partly owing to his exceeding modesty. He was over-ready to acknowledge the value to himself of other people's ideas, and he under-estimated the strength of the illumination which his own mind threw upon those ideas, transforming them from guesses into probable hypotheses, confirming them by his vast and varied knowledge, and building a superstructure where they had laid but an uncertain foundation. The question was in the air ; guessing replies of great interest were made by a few who doubted the received belief; but they were not satisfying answers and they did not effect a revolution. Goethe in Germany, Erasmus Darwin in England,' and

It is worth while to reproduce here a few sentences from Erasmus Darwin's "Zoonomia," showing how acutely he guessed in the direction of evolution.

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"When we revolve in our minds, first, the great changes which we see naturally produced in animals after their nativity. Secondly, when we think over the great changes introduced into various animals by artificial or accidental cultivation. . . . Thirdly, when we enumerate the great changes produced in the species of animals before their nativity. . . . Fourthly, when we revolve in our minds the great similarity of structure which obtains in all the warm-blooded animals. . . . Fifthly, from their first rudiment or primordium to the termination of their lives, all animals undergo perpetual transformations, which are in part produced by their own exertions; . . . and many of these acquired forms or propensities are transmitted to their posterity. . . . A great want of one part of the animal world has consisted in the desire of the exclusive possession of the female; and these have acquired weapons to combat each other for this purpose. . . . The final cause of this contest amongst the males seems to be that the strongest and most active animal should propagate the species, which should thence become improved. Another great want consists in the means of procuring food, which has diversified the forms of all species of animals. . . . All which seem to have been gradually produced during many generations by the

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Geoffroy Saint Hilaire in France, came independently to similar conclusions as to the mutability of species; and Lamarck followed with several well-known works in 1801-15, in which he upholds the doctrine that all species, including man, are descended from other species. As Darwin says, Lamarck first did the eminent service of arousing attention to the probability of all change in the organic, as well as in the inorganic world, being the result of law, and not of miraculous interposition. He saw the difficulty of distinguishing between species and varieties, the almost perfect gradation of form in some groups, and the great similarity of domestic breeds of animals to such species. He believed that some degree of change was produced by the physical conditions of life, the intercrossing of species, and by habits causing increased use or disuse of parts. Indeed he thought very many remarkable adaptations, such as that of the neck of the giraffe for browsing on trees, were the effect of habit. But he attributed, perhaps, more to a law of progressive development impressed on all forms of life, perpetual endeavour of the creatures to supply the want of food, and to have been delivered to their posterity with constant improvement of them for the purpose required. . . . The third great want among animals is that of security, which seems much to have diversified the forms of their bodies and the colour of them. . . The contrivances for the purposes of security extend even to vegetables.... Would it be too bold to imagine that in the great length of time since the earth began to exist . . . all warm-blooded animals have arisen from one living filament, which the Great First Cause endued with animality; . . . possessing the faculty of con- ' tinuing to improve by its own inherent activity, and of delivering down those improvements by generation to its posterity, world without end!".

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which thus would all in time gradually cease to be lowly, their place being taken by new forms continually or "spontaneously" generated.

It does not appear that Lamarck would by any means have sufficed to convince Darwin, judging from his references to him in his Journal and the "Origin.” Here is the passage in which in the second edition of his Journal he refers to the blindness of the Brazilian Tucutuco, or Ctenomys, a rodent or gnawing mammal with the habits of a mole: "Considering the strictly subterranean habits of the Tucutuco, the blindness, though so common, cannot be a very serious evil; yet it appears strange that any animal should possess an organ frequently subject to be injured. Lamarck would have. been delighted with this fact had he known it when speculating (probably with more truth than usual with him) on the gradually acquired blindness of the Aspalax, a gnawer living underground, and of the Proteus, a reptile living in dark caverns filled with water, in both of which animals the eye is in an almost rudimentary state, and is covered with a tendinous membrane and skin.

In the Tucutuco, which, I believe, never comes to the surface of the ground, the eye is rather larger (than in the mole), but often rendered blind and useless, though without apparently causing any inconvenience to the animal no doubt Lamarck would have said that the Tucutuco is now passing into the state of the Aspalax and Proteus." Many years afterwards in the "Origin of Species" Darwin referred to the "erroneous views and grounds of opinion of Lamarck.”

No doubt some impulse to Darwin's views in this