As the sheets of this Lecture are passing through the press, Sir Henry Roscoe, as President of the British Association, has delivered a brilliant and essentially scientific address. On the subject of chemistry none can speak with a voice more authoritative: and on this very question he writes as follows: ‘But now the question may well be put—Is any limit set to this synthetic power of the chemist? Although the danger of dogmatizing as to the progress of science has already been shown in too many instances, yet one cannot help feeling that the barrier which exists between the organized and unorganized worlds is one which the chemist sees no chance of breaking down. It is true that there are those who profess to foresee that the day will arrive, when the chemist, by a succession of constructive efforts, may pass beyond albumen, and gather the elements of lifeless matter into a living structure. Whatever may be said regarding this from other standpoints, the chemist can only say that at present no such problem lies within his province. Protoplasm, with which the simplest manifestations of life are associated, is not a compound, but a structure built up of compounds. The chemist may successfully synthesize any of its component molecules, but he has no more reason to look forward to the synthetic production of the structure than to imagine that the synthesis of gallic acid leads to the artificial production of gall-nuts.’[20] To assume, then, that by starting with atoms in equilibriated motions, uncounted millenniums of ages ago, and that by adding atoms and groups of atoms, with altered and re-altered motions as the ages roll away, with the result that at last, with these factors and no others, we shall get organism and life, is, surely, as fallacious as to explain Millais’s picture of the Huguenots as having been brought about by a skilful arrangement of palettes and brushes, easels and pigments. Now let it be clearly recalled that Charles Darwin involved himself in none of this philosophic ambiguity. To him life was more than a complexity of elementary atoms affected by motion. It was something he could not ‘explain.’ He postulated, therefore, the unexplained presence of ‘primordial living germs,’ endowed with the properties, which, experience teaches, are possessed by living matter to-day. How, in the great past, mineral and gaseous matters on this earth were, as a question of scientific method, so affected as to become living matter is, to our present resources at least, impenetrable. [Footnote 20: The _Times_ report of the address of Sir H. E. Roscoe before the British Association at Manchester.—_Times_, September 1, 1887.] ‘Flower in the crannied wall, I pluck you out of the crannies; I hold you here, root and all, in my hand, Little flower.—But _if_ I could understand What you are, root and all, and all in all, I should know what God and man is.’