In concluding, the author made some most profoundly suggestive remarks, which went far to revolutionise our conception of plants. "It has often been vaguely asserted that plants are distinguished from animals by not having the power of movement. It should rather be said that plants acquire and display this power only when it is of some advantage to them; this being of comparatively rare occurrence, as they are affixed to the ground, and food is brought to them by the air and rain. We see how high in the scale of organisation a plant may rise, when we look at one of the more perfect tendril-bearers. It first places its tendrils ready for action, as a polypus places its tentacula. If the tendril be displaced, it is acted on by the force of gravity, and rights itself. It is acted on by the light, and bends towards or from it, or disregards it, which ever may be most advantageous. During several days the tendrils, or internodes, or both, spontaneously revolve with a steady motion. The tendril strikes some object, and quickly curls round and firmly grasps it. In the course of some hours it contracts into a spire, dragging up the stem, and forming an excellent spring. All movements now cease. By growth the tissues soon become wonderfully strong and durable. The tendril has done its work, and has done it in an admirable manner." The labour of revising the successive editions of the "Origin of Species," together with prolonged ill-health, delayed the fulfilment of the promise given in that work, that the facts upon which it was based should be published. It was not till 1868 that the first instalment, "The Variation of Animals and Plants under Domestication," was given to the world, in two large volumes, with numerous illustrations. The author's design was to discuss in a second work the variability of organic beings in a state of nature, and the conversion of varieties into species, the struggle for existence and the operation of natural selection, and the principal objections to the theory, including questions of instinct and hybridisation. In a third work it was intended to test the principle of natural selection by the extent to which it explains the geological succession of organic beings, their distribution in past and present times, and their mutual affinities and homologies. The two latter works were never completed, in consequence of ill-health, and the labour involved in dealing with objections to and new facts in support of the "Origin," and of the other works which at various times it became important to complete. But many portions of these subjects were admirably dealt with by disciples. In some cases Darwin's views led to the rapid growth of a new science, such as that of comparative embryology, and it would not have been possible for him to cope with and interpret the multitude of new and astonishing facts discovered, which changed the face of organic nature as viewed by biologists. By doing