[17] At a meeting of the British Association in 1905, Professor H. A. Miers, in a lecture on ‘The Growth of a Crystal,’ is reported to have said, The most wonderful feature of crystals was the manner in which they grew, just as though they were living things. Two features deserved special attention. The first was the remarkable power crystals possessed of healing themselves when mutilated. If a growing crystal were removed from a solution, broken at one of its corners, and re-immersed in the solution, it would continue to grow, and as it grew would restore the missing part, and become once more a completely symmetrical figure. This power of continuing to grow was possessed by a crystal even after countless ages, so soon as it was immersed into the appropriate solution. In this sense the crystal was immortal, for it never lost its vitality, or power of growing. The other remarkable feature was the growth of crystals in over-saturated solutions. In solutions only slightly over-saturated, no spontaneous generation of crystals was possible. It was true that a solution only slightly over-saturated would often begin to crystallize, apparently spontaneously, when exposed to the air, but this was because there were minute crystal fragments of the dissolved substance floating about in the air which got into the solution with the dust and so inoculated the solution with crystal germs, just as the human body might be inoculated with disease by a disease germ. If these germs were kept out, the solution would not crystallize until it was very strongly over-saturated, and then, at a certain strength, it would suddenly begin to crystallize spontaneously and with great rapidity.—_Times_, August 5, 1907. [18] The Nature and Origin of Life (Eng. trans.), p. 250. [19] It is not to be assumed, however, that these substances are merely passive objects in the process. The life which is in them has doubtless as much to do with the result as the life which is in the plant. This is a side of the question which calls for further investigation. [20] It is however suggested by Professor E. Ray Lankester, in his article, ‘Protozoa,’ in the Encyclopædia Britannica, that the most primitive forms of organic life did not possess chlorophyll but fed on albuminoids, etc., which constituted the earliest steps in their own evolution. [21] In Beddard’s Animal Coloration note is taken of the green fur of the sloth as a most uncommon if not unique phenomenon. It has been ascertained that the sloth has grooved or fluted hairs, which form the habitat of a minute green fungus to which the colour is due. [22] Or starch, which easily decomposes into sugar, and which is composed of the same elements. [23] Ray Lankester, _op. cit._