[15] In 1896, by Messrs. Macmillan. [16] In one instance, at least, Darwin had pictured in his imagination the steps by which a "strange and odious instinct" may have been developed from comparatively innocent beginnings. He was referring to the ejection by the young cuckoo of its companions from the nest. "I can see no special difficulty in its having gradually acquired, during successive generations, the blind desire, the strength and structure necessary for the work of ejection." "The first step towards the acquisition of the proper instinct might have been mere unintentional restlessness on the part of the young bird."--_Origin of Species_, p. 200. [17] Pp. 135, f. [18] P. 142. [19] P. 143. [20] P. 144. [21] P. 232. {68} CHAPTER VII LATER SCIENCE The position, as we have described it, was that which may be said to have existed up to about twenty years ago. Since then much new light has come. Indeed, Lord Kelvin, speaking at Clerkenwell on February 26th, 1904, is reported in _The Times_ to have said, referring to the extraordinary progress of scientific research, that it "had, perhaps, been even more remarkable and striking at the beginning of the twentieth century than during the whole of the nineteenth." Let us take first that which he had more particularly in mind, the advance in the knowledge of the constitution of Matter. In an address delivered before the British Association at Bradford in 1873, Clerk Maxwell had stated the conclusions to which science had, up to that time, been led in its investigations of matter. Throughout the natural universe it had been shewn, by Spectrum Analysis, that matter is built up of {69} molecules. These molecules, according to the most competent judgment, were incapable of sub-division without change of substance, and were absolutely fixed for each substance. "A molecule of hydrogen, for example, whether in Sirius, or in Arcturus, executes its vibrations in precisely the same time." The relations of the parts and movements of the planetary systems may and do change, but "the molecules--the foundation-stones of the natural universe--remain unbroken and unworn." As a result of this, it was maintained that "the exact equality of each molecule to all others of the same kind gives it, as Sir John Herschel has well said, the essential character of being a manufactured article, and precludes the idea of its being eternal and self-existent." "Not that science is debarred from studying the internal mechanism of a molecule which she cannot take to pieces ... but, in tracing back the history of matter, science is arrested when she assures herself, on the one hand, that the molecule has been made, and on the other that it has not been made by any of the processes we call natural."