Life and Letters of Charles Darwin — Volume 1

What capital news from Tasmania: it really is a very remarkable and creditable fact to the Colony. (This refers to an unsolicited grant by the Colonial Government towards the expenses of Sir J. Hooker's 'Flora of Tasmania.') I am always building veritable castles in the air about emigrating, and Tasmania has been my head-quarters of late; so that I feel very proud of my adopted country: is really a very singular and delightful fact, contrasted with the slight appreciation of science in the old country. I thank you heartily for your letter this morning, and for all the gratification your Dedication has given me; I could not help thinking how much — would despise you for not having dedicated it to some great man, who would have done you and it some good in the eyes of the world. Ah, my dear Hooker, you were very soft on this head, and justify what I say about not caring enough for your own fame. I wish I was in every way more worthy of your good opinion. Farewell. How pleasantly Mrs. Hooker and you must rest from one of your many labours...

Again farewell: I have written a wonderfully long letter. Adios, and God bless you.

My dear Hooker, ever yours, C. DARWIN.

P.S. — I have just looked over my rambling letter; I see that I have not at all expressed my strong admiration at the amount of scientific work, in so many branches, which you have effected. It is really grand. You have a right to rest on your oars; or even to say, if it so pleases you, that "your meridian is past;" but well assured do I feel that the day of your reputation and general recognition has only just begun to dawn.

[In September, 1854, his Cirripede work was practically finished, and he wrote to Dr. Hooker:

"I have been frittering away my time for the last several weeks in a wearisome manner, partly idleness, and odds and ends, and sending ten thousand Barnacles out of the house all over the world. But I shall now in a day or two begin to look over my old notes on species. What a deal I shall have to discuss with you; I shall have to look sharp that I do not 'progress' into one of the greatest bores in life, to the few like you with lots of knowledge."]

CHAPTER 1.X. — THE GROWTH OF THE 'ORIGIN OF SPECIES.'

[The growth of the 'Origin of Species' has been briefly described in my father's words (above). 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 (MS. Journals, page 468.) 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 (1st edition page 353; 2nd edition page 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."

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 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 edition page 61; 2nd edition page 53) must have been one of the earliest instances noticed by him of the existence of representative species — a phenomenon which we know ('Autobiography,') struck him deeply. The discussion on introduced animals (1st edition page 139; 2nd edition page 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 (1st edition page 98; 2nd edition page 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 a 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 edition page 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 edition page 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 edition, but otherwise are similar to the corresponding passages in the 1st edition. Thus, in describing the blind Tuco-tuco (1st edition page 60; 2nd edition page 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 edition (page 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 1st edition, 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 led up to a strong statement of the intensity of the struggle for life. Then follows a comparison between rarity (In the second edition, page 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.) 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, 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 edition) 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 sufficiently 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 edition page 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 edition page 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 (page 461) without comment. Whereas in the second edition (page 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) (In the extracts from the note-book ordinary brackets represent my father's parentheses.) 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. (On the first page of the note-book, is written "Zoonomia"; this seems to refer to the first few pages in which reproduction by gemmation 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 1844, and these would have no doubt contained the most interesting extracts.)

"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 of evolution to the "whole organic kingdom" from plants to man.

"If we choose to let conjecture run wild, then animals, our fellow brethren in pain, disease, death, suffering and famine — our slaves in the most laborious works, our companions in our amusements — they may partake [of?] our origin in one common ancestor — we may be all melted together."

"The different intellects of man and animals not so great as between living things without thought (plants), and living things with thought (animals)."

The following extracts are again concerned with an a priori view of the probability of the origin of species by descent ["propagation," he called it.].

"The tree of life should perhaps be called the coral of life, base of branches dead; so that passages cannot be seen."

"There never may have been grade between pig and tapir, yet from some common progenitor. Now if the intermediate ranks had produced infinite species, probably the series would have been more perfect."

At another place, speaking of intermediate forms he says: —

"Cuvier objects to propagation of species by saying, why have not some intermediate forms been discovered between Palaeotherium, Megalonyx, Mastodon, and the species now living? Now according to my view (in S. America) parent of all Armadilloes might be brother to Megatherium — uncle now dead."

Speaking elsewhere of intermediate forms, he remarks: —

"Opponents will say — 'show them me.' I will answer yes, if you will show me every step between bulldog and greyhound."

Here we see that the case of domestic animals was already present in his mind as bearing on the production of natural species. The disappearance of intermediate forms naturally leads up to the subject of extinction, with which the next extract begins.

"It is a wonderful fact, horse, elephant, and mastodon, dying out about same time in such different quarters.

"Will Mr. Lyell say that some [same?] circumstance killed it over a tract from Spain to South America? — (Never).

"They die, without they change, like golden pippins; it is a GENERATION OF SPECIES like generation OF INDIVIDUALS.

"Why does individual die? To perpetuate certain peculiarities (therefore adaptation), and obliterate accidental varieties, and to accommodate itself to change (for, of course, change, even in varieties, is accommodation). Now this argument applies to species.

"If individual cannot propagate he has no issue — so with species.

"If SPECIES generate other SPECIES, their race is not utterly cut off: — like golden pippins, if produced by seed, go on — otherwise all die.

"The fossil horse generated, in South Africa, zebra — and continued — perished in America.

"All animals of same species are bound together just like buds of plants, which die at one time, though produced either sooner or later. Prove animals like plants — trace gradation between associated and non-associated animals — and the story will be complete."

Here we have the view already alluded to of a term of life impressed on a species.