Chapter 13

LAMARCK AND MR. DARWIN

It will have been seen that in the preceding pages the theory of evolution, as originally propounded by Lamarck, has been more than once supported, as against the later theory concerning it put forward by Mr. Darwin, and now generally accepted.

It is not possible for me, within the limits at my command, to do anything like justice to the arguments that may be brought forward in favour of either of these two theories. Mr. Darwin's books are at the command of every one; and so much has been discovered since Lamarck's day, that if he were living now, he would probably state his case very differently; I shall therefore content myself with a few brief remarks, which will hardly, however, aspire to the dignity of argument.

According to Mr. Darwin, differentiations of structure and instinct have mainly come about through the accumulation of small, fortuitous variations without intelligence or desire upon the part of the creature varying; modification, however, through desire and sense of need, is not denied entirely, inasmuch as considerable effect is ascribed by Mr. Darwin to use and disuse, which involves, as has been already said, the modification of a structure in accordance with the wishes of its possessor.

According to Lamarck, genera and species have been evolved, in the main, by exactly the same process as that by which human inventions and civilisations are now progressing; and this involves that intelligence, ingenuity, heroism, and all the elements of romance, should have had the main share in the development of every herb and living creature around us.

I take the following brief outline of the most important part of Lamarck's theory from vol. xxxvi. of the Naturalist's Library (Edinburgh, 1843):-

"The more simple bodies," says the editor, giving Lamarck's opinion without endorsing it, "are easily formed, and this being the case, it is easy to conceive how in the lapse of time animals of a more complex structure should be produced, FOR IT MUST BE ADMITTED AS A FUNDAMENTAL LAW, THAT THE PRODUCTION OF A NEW ORGAN IN AN ANIMAL BODY RESULTS FROM ANY NEW WANT OR DESIRE IT MAY EXPERIENCE. The first effort of a being just beginning to develop itself must be to procure subsistence, and hence in time there comes to be produced a stomach or alimentary cavity." (Thus we saw that the amoeba is in the habit of "extemporising" a stomach when it wants one.) "Other wants occasioned by circumstances will lead to other efforts, which in their turn will generate new organs."

Lamarck's wonderful conception was hampered by an unnecessary adjunct, namely, a belief in an inherent tendency towards progressive development in every low organism. He was thus driven to account for the presence of many very low and very ancient organisms at the present day, and fell back upon the theory, which is not yet supported by evidence, that