11 APRIL 1958, Page 19

BOOKS

Favourable Variations

BY MAGNUS PYKE THE AUTOBIOGRAPHY OF CHARLES DARWIN, 1809- 1882 Edited by Nora Bailow. (Collins, 16s.) 1HE DARWIN READER. Edited by M. Bates and P. S. Humphrey. (Macmillan, 30s.) DR. ERASMUS DARWIN, Charles Darwin's grandfather, lived from 1731 to 1802. His PUblished works • posegsed at their time an immense vogue. And when he wrote, great things Were in the air. Science and Philosophy were an- nouncing the approaching perfectability of Man --and that soon. Signs of Progress were all around. The steam engine had been invented. The mechanisation of factories, the spinning jenny, the,, rising upsurge of the Industrial Revolution With the great increase it brought in wealth— all these were symbols of Man's power over Nature and demonstrated the fact that the pur- Pose of all the Creator's works was for the benefit of mankind. Erasmus Darwin was an imposing Prophet of these times. Zoonoinia, published in 1794-96 contained his account of Generation or Descent. But his theories were built of a heavy superstructure of speculation on an insufficient foundation of fact; indeed, years before Charles Darwin was born, Coleridge coined the word `darwinising' to describe wild pseudo-scientific speculation.

The publication of the Origin of Species in November, 1859, brought a whole philosophical epbch to an end. It is interesting to consider for a Moment why this one book exerted the influence it did. Firstly, of course, the thesis in it, that of natural selection, was supported by an immense Mass of observations dating back to thOse col- lected by Darwin as a young man of twenty-two in 1831 and during his subsequent five years spent as unpaid biologist in HMS Beagle on her voyage round the world. Then again, the discovery of natural selection came when it was badly needed. ?rofessor Wolley, of Cambridge, writing much later, described the immediate and overwhelming effect it had on his mind when he read the part 'of the Journal of the Linnean Society in which it was first described. 'Herein was contained a Perfectly simple solution of all the difficulties Which had been troubling me for months past.' °In Darwin, himself impressed by the success of the Origin of Species—the first edition of 1,250 copies was sold on the day of publication, 16,000 copies were sold in England and it was trans- lated into almost every European language, in- cluding Bohemian and Polish—attributed it to the fact that it was a condensed version of a much 'larger manuscript. 'Had I published on the scale in which I began to write in 1856,' he com- ments in his autobiography,* 'very few would have had the patience to .read it.' It must also be Pointed out for the benefit of modern scientists that it was written in clear, educated English.

The centenary of the Origin of Species falls

into today. Darwin's book finally broke through the preSent world in which science is the dominant philosophy. Man was seen to be no longer a special creature little, lower than the

angels and separated from the brutes, but took his place. with the biological progression of other species. Geologists were freed from the necessity of assuming the earth to be a miraculous con- struction produced by Jehovah in 4004 BC. In- telligent men were now able to address their minds to the grouping of facts so that general laws or :conclusions might be drawn from them. This, indeed, has been the basic premiss of science ever since : that there is an underlying regularity throughout Nature which it is within the ability of the human mind to discover.

In the hundred years since Dam in wrote we have exploited the scientific freedom he gave us. Three major advances have occurred in biology. One was the acceptance that the cell was the unit of life: This has been in its way as fundamental to the science of biology as the atomic theory has been to chemistry. From it we have been able to elucidate in our own times the underlying unity in the mechanism of all life. We carry in our human cells the basic chain of chemical links by means of which priMitive unicellular creatures obtained energy by fermentation before green plants existed on earth or oxygen occurred in the terrestial atmosphere. Part of the mechanism of photosynthesis in green plant cells—a mechan- ism, let us note, -coming later in biochemical evolution—we also possess still, as well as our subsequently evolved' power of respiration. A second post-Darwin milestone was Mendel's theory of genetics and a third major advance in scientific thinking is happening now. It is the elucidation by means of the new and sharper tools provided by physics—X-ray crystal- lography and the like—of the chemical construc- tion of the genes, which were no more than a hypothesis when Mendel deduced their existence. Today, we .seem near to an understanding of the chemical molecules by whose division one cell becomes two, and we know something, per- haps, of the means by which a single dividing cell tells its progeny whether to become a fruit fly or a man.

With all this going on, now is a good time to look back at Darwin. Lady Barlow, his grand- daughter, has re-edited his autobiography, first published in 1887. It is a sincere and touching document written primarily for his children during the period between his sixty-eighth and seventy-fourth years. There is a charming descrip- tion of his childhood, of his father the successful doctor, of his university career first at Edinburgh and then at Cambridge from which he proposed to enter the Church. The expedition in the Beagle was the merest chance—his father strongly op- posed it as a waste of the young man's time. The description of how he came to conceive the theory of natural selection is most vividly written. 'In October 1838 . . I happened to read for amuse- ment Malthus on Population, and being well pre- pared to appreciate the struggle fix. existence 1,,,h;(7h everywhere goes on, from long-continued oo,,.tvation of the habits of animals and plants, it at once struck me that under these circum- stances favourable variation§ would tend to be preserved, and unfavourable ones to be destroyed. . . . I can remember the very spot in the road whilst in my carriage, when to my joy the solution occurred tome.'

Science gives us material wealth and mechani- cal power. But, above all, it provides us with our understanding of the natural universe in which we live. We are interested in Darwin because of the way he thought and the .way he organised facts into a coherent system. It is because• of the discoveries by which he advanced the knowledge and understanding and hence the stature of man- kind as a thinking creature that we concern our- selves with the details of his behaviour; with the extraordinary Victorian ill-health, for example, by which, like Florence Nightingale, he gave himself the time and the-isolation which were probably essential for the maturing of his ideas. Interest in Darwin is well served by Professor Bates, of the UniVersity of ' Michigan, and his collaborator Dr. Humphrey in The Darwin Reader,t where we are presented not only with the more interesting sections of the 1887 auto- biography but with substantial extracts from The Voyage of the Beagle, The Origin of Species, The Descent of Man and The Expression of the Emotions. Lady- BarloW's- contribution, on the other hand, has been to restore to the auto- biography a number of passages deleted for family reasons at the time it was published and, among other additions, to include an appendix of fifty-four pages solelyconcerned with a dreary quarrel on some small point of priority between Darwin and Samuel Butler, The Autobiography as a whole gives us a remarkable picture of what Darwin was like. The. Darwin Reader tells us about Darwin too, but it also enables us to knoW something of what he thought.