Rustic Sounds, and Other Studies in Literature and Natural History

by Sir Francis Darwin

I once heard a celebrated physicist describe how he explained to an American business man an elaborate spectroscope for examining the sun. The American asked what good it was. The physicist explained that with it you can discover whether or

no sodium exists in the sun. The American was silent for some time, and then said, “But who the ’nation cares whether there is sodium in the sun or not?” He had not the scientific spirit which does care about sodium in the sun.

Scientific discovery is, as I said, made up of a series of prophecies. You observe fact No. 1, and you say if this be so No. 2 ought to be true, and on examination you find this is true, and No. 2 suggests No. 3. Or else you find 2 not to be true; this makes you suspect your original fact, and on carefully going over your observation you find No. 1 was a mistaken observation. The successful man of science is one to whom familiar objects suggest those prophecies generally known as theories. My father was remarkable for not letting what seem to be trifling facts pass without suggesting to him a theory. The flies that are caught on the sundew must have been seen by innumerable people—but it remained for him to prove the truth of his guess that some plants possess digestive ferments like our own, and live on the insects they catch and digest.

The art of being guided by slight indications is sometimes called the method of Zadig, which I learn from Mr. Huxley’s essay and not from Voltaire. Mr. Huxley points out that it is not only possible thus to prophesy what will happen, but also to determine what has happened; and he suggests that there should be a word ‘backtell’ as well as foretell. Zadig, who was an oriental philosopher, met one day the King’s servants in great trouble about the loss of their master’s favourite horse.

When asked whether he had seen it he said, “A fine galloper, is it not? small hoofed, five feet high, tail 3½ feet long. Cheek-pieces of the bit 23-carat gold, shoes silver.” They of course begged to know where it was, and he said he had not seen it.

This will be recognised as the method of Sherlock Holmes, but it is also the method of science. Surely you would like to become scientific under the guidance of that great man. Of course you are not to be Watsons, but actual detectives, with Watsons of your own to admire you. And lest you should fear that the scientific method is alarmingly difficult, I may add that the method of Zadig or Sherlock Holmes, or of science in general, is nothing more than glorified common-sense.

It is difficult to talk about a subject which interests one without seeming to claim that it is superior to all others. I have not meant to imply this. I have only tried to explain in what way science differs from some other sort of knowledge. Nor do I wish to imply that the mind that excels in science is better or worse than that which one finds in a great literary man. An eminent oar is worthy of as much respect as a great cricketer, but he is eminent in a different way.

I am glad to think that there are points in which science, literature, and art are equally excellent—namely, in giving to mankind some of the deepest pleasures of which he is capable, in making him realise the wonder, the beauty and the romance of the world. I spoke of the power of science in knitting together isolated facts into a

theory. And such a theory may become so all embracing that it is called a law of nature. Those great generalisations, the laws of gravity and the laws of evolution, or the laws of chemical combination, have a beauty and dignity which appeal to everyone.

And on the practical rather than on the theoretical, side there is wonder, and to my mind beauty, in the bigness and in the smallness of the spaces that man can deal with. The astronomer measures out his work, not by miles, but by the inconceivable distance that light can travel in a year. The man who studies bacteria measures by the micron, 25,000 of which go to the inch. To me there is more fascination in the very small than in the other extreme. It is wonderful to think that a plant—a big tree for instance—is made up of countless millions of cells, each of which was built by a minute protoplasmic body, which Huxley has compared to a delicate Ariel imprisoned like Shakespeare’s sprite in an oak-tree.