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CHAPTER X.

THE GROWTH OF THE

ORIGIN OF SPECIES.'

[On page 67, the growth of the 'Origin of Species' has been briefly described in my father's words. The letters given in the present and following chapters will illustrate and amplify the history thus sketched out.

It is clear that in the early part of the voyage of the Beagle he did not feel it inconsistent with his views to express himself in thoroughly orthodox language as to the genesis of new species. Thus in 1834 he wrote at Valparaiso : "I have already found beds of recent shells yet retaining their colour at an elevation of 1300 feet, and beneath, the level country is strewn with them. It seems not a very improbable conjecture that the want of animals may be owing to none having been created since this country was raised from the sea."

This passage does not occur in the published 'Journal, the last proof of which was finished in 1837; and this fact harmonizes with the change we know to have been proceeding in his views. But in the published 'Journal' we find passages which show a point of view more in accordance with orthodox theological natural history than with his later views. Thus, in speaking of the birds Synallaxis and Scytalopus (ist edit. p. 353 ; 2nd edit. p. 289), he says : “When finding, as in this case, any animal which seems to play so insignificant a part in the great scheme of nature, one is apt to wonder why a distinct species should have been created."

* MS. Journals, p. 468.

A comparison of the two editions of the 'Journal' is instructive, as giving some idea of the development of his views on evolution. It does not give us a true index of the mass of conjecture which was taking shape in his mind, but it shows us that he felt sure enough of the truth of his belief to allow a stronger tinge of evolution to appear in the second edition. He has mentioned in the Autobiography (p. 68) that it was not until he read Malthus that he got a clear view of the potency of natural selection. This was in 1838-a year after he finished the first edition (it was not published until 1839), and five years before the second edition was written (1845). Thus the turning-point in the formation of his theory took place between the writing of the two editions.

I will first give a few passages which are practically the same in the two editions, and which are, therefore, chiefly of interest as illustrating his frame of mind in 1837.

The case of the two species of Molothrus (1st edit. p. 61; 2nd edit. p. 53) must have been one of the earliest instances noticed by him of the existence of representative species—a phenomenon which we know (* Autobiography,' p. 68) struck him deeply. The discussion on introduced animals (ist edit. p. 139; 2nd edit. p. 120) shows how much he was impressed by the complicated interdependence of the inhabitants of a given area.

An analogous point of view is given in the discussion (ist edit. p. 98 ; 2nd edit. p. 85) of the mistaken belief that large animals require, for their support, a luxuriant vegetation; the incorrectness of this view is illustrated by the comparison of the fauna of South Africa and South America, and the vegetation of the two continents. The interest of the discussion is that it shows clearly our à priori ignorance of the conditions of life suitable to any organism.

There is a passage which has been more than once quoted as bearing on the origin of his views. It is where he discusses the striking difference between the species of mice on the east and west of the Andes (1st edit. p. 399): “Unless we suppose the same species to have been created in two different countries, we ought not to expect any closer similarity between the organic beings on the opposite sides of the Andes than on shores separated by a broad strait of the sea." In the 2nd edit. p. 327, the passage is almost verbally identical, and is practically the same.

There are other passages again which are more strongly evolutionary in the 2nd edit., but otherwise are similar to the corresponding passages in the ist edition. Thus, in describing the blind Tuco-tuco (1st edit. p. 60; 2nd edit. p. 52), in the first edition he makes no allusion to what Lamarck might have thought, nor is the instance used as an example of modification, as in the edition of 1845.

A striking passage occurs in the 2nd edit. (p. 173) on the relationship between the “extinct edentata and the living sloths, ant-eaters, and armadillos."

“This wonderful relationship in the same continent between the dead and the living, will, I do not doubt, hereafter throw more light on the appearance of organic beings on our earth, and their disappearance from it, than any other class of facts.".

This sentence does not occur in the ist edit., but he was evidently profoundly struck by the disappearance of the gigantic forerunners of the present animals. The difference between the discussions in the two editions is most instructive. In both, our ignorance of the conditions of life is insisted on, but in the second edition, the discussion is made to lead up to a strong statement of the intensity of the struggle for life. Then follows a comparison between rarity * and extinction, which introduces the idea that the preservation and dominance of existing species depend on the degree in which they are adapted to surrounding conditions. In the first edition,

* In the second edition, p. 146, the destruction of Niata cattle by droughts is given as a good example of our ignorance of the causes of rarity or extinction. The passage does not occur in the first edition,

he is merely "tempted to believe in such simple relations as variation of climate and food, or introduction of enemies, or the increased number of other species, as the cause of the succession of races." But finally (1st edit.) he ends the chapter by comparing the extinction of a species to the exhaustion and disappearance of varieties of fruit-trees : as if he thought that a mysterious term of life was impressed on each species at its creation.

The difference of treatment of the Galapagos problem is of some interest. In the earlier book, the American type of the productions of the islands is noticed, as is the fact that the different islands possess forms specially their own, but the importance of the whole problem is not so strongly put forward. Thus, in the first edition, he merely says :

“This similarity of type between distant islands and continents, while the species are distinct, has scarcely been sufficientl, noticed. The circumstance would be explained, according to the views of some authors, by saying that the creative power had acted according to the same law over a wide area."-(1st edit. p. 474.)

This passage is not given in the second edition, and the generalisations on geographical distribution are much wider and fuller. Thus he asks :

“Why were their aboriginal inhabitants, associated ... in different proportions both in kind and number from those on the Continent, and therefore acting on each other in a different manner-why were they created on American types of organisation?"-(2nd edit. p. 393.)

The same difference of treatment is shown elsewhere in this chapter. Thus the gradation in the form of beak presented by the thirteen allied species of finch is described in the first edition (p. 461) without comment. Whereas in the second edition (p. 380) he concludes :

“One might really fancy that from an original paucity of birds in this Archipelago, one species has been taken and modified for different ends."

On the whole it seems to me remarkable that the difference

between the two editions is not greater; it is another proof of the author's caution and self-restraint in the treatment of his theory. After reading the second edition of the ‘Journal,' we find with a strong sense of surprise how far developed were his views in 1837. We are enabled to form an opinion on this point from the note-books in which he wrote down detached thoughts and queries. I shall quote from the first note-book, completed between July 1837 and February 1838 : and this is the more worth doing, as it gives us an insight into the condition of his thoughts before the reading of Malthus. The notes are written in his most hurried style, so many words being omitted, that it is often difficult to arrive at the meaning. With a few exceptions (indicated by square brackets) * I have printed the extracts as written; the punctuation, however, has been altered, and a few obvious slips corrected where it seemed necessary. The extracts are not printed in order, but are roughly classified.

"Propagation explains why modern animals same type as extinct, which is law, almost proved."

“We can see why structure is common in certain countries when we can hardly believe necessary, but if it was necessary to one forefather, the result would be as it is. Hence antelopes at Cape of Good Hope; marsupials at Australia.”

Countries longest separated greatest differences—if separated from immersage, possibly two distinct types, but each having its representatives—as in Australia.”

“Will this apply to whole organic kingdom when our planet first cooled "

The two following extracts show that he applied the theory

* In the extracts from the note-book ordinary brackets represent my father's parentheses.

| On the first page of the note-book, is written“ Zoonomia "; this seems to refer to the first few pages in which reproduction by genimation is discussed, and where the “Zoonomia” is mentioned. Many pages have been cut out of the note-book, probably for use in writing the Sketch of 1841, and these would have no doubt contained the most interesting

extracts.

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