form of consciousness, but which is due to a purely organic reaction. It is scarcely satisfactory to say that the spermatozoids “possess a certain power of perception, by which their movements are guided.”[6] If consciousness be present, it is probably merely an accompaniment of the response, and has no directive influence on its nature and character. In the higher plants, as in the higher animals, the differentiation and the orderly marshalling of the cell-progeny arising from the coalescent male and female elements, afford, during development, examples of corporate organic behaviour which can be more readily described than explained, but which not less clearly subserve definite biological ends, and in many cases, such as the direction of growth in radicles and roots, the curling of tendrils, and the reaction to the influence of light and warmth, are related to and evoked by the environing conditions. More closely resembling familiar modes of behaviour in animals are such movements as are seen in the “tentacles” which project from the upper surface and margin of the Sun-dew leaf. Their knobbed ends secrete a sticky matter, which glistens in the sun, and to which small foreign bodies readily adhere. If particles of limestone, sand, or clay, such as may be blown by the wind, touch and stick to these knobs, there follows an exudation of acid liquid, but no marked and continuous change occurs in the position of the tentacles. But should an insect alight on the leaf, or a small piece of meat be placed upon the tentacles, not only is there a discharge of acid juice, but a ferment is also produced, which has a digestive action on the nitrogenous matter. Slowly the tentacle curves inwards and downwards, as one’s finger may bend towards the palm of one’s hand; neighbouring tentacles also turn towards and incline on to the stimulating substance; then others, further off, behave in a similar way, until all the tentacles, some two hundred in number, are inflected and converge upon the nitrogenous particle. Nay, more: “When two little bits of meat are placed simultaneously on the right and left halves of the same Sun-dew leaf, the two hundred tentacles divide into two groups, and each one of the groups directs its aim to one of the bits of meat.”[7] [Illustration: FIG. 6.--Sun-dew (_Drosera_). Leaf (enlarged) with the tentacles on one side inflected over a bit of meat placed on the disc. (From Darwin’s “Insectivorous Plants.”)]