many only open their leaves or flowers to the sunshine, while others the plantæ tristes, the watchmen of the flower garden, only spread abroad their beauties to the night. Other plants exhibit a certain amount of irritability, or sensitive qualities, under mechanical or chemical stimuli. The Drosera and Dionæa woo the unwary fly to its destruction shutting it up in deadly folds, while the Mimosa sensitiva and a few others will shriek from the most delicate touch, and may be laid asleep, during any severe operation of the gardener, under the influence of opium or Chloroform. If on the other hand we assume as the characteristic of the animal, its capability of changing its position, we still find similar properties in the plant; for vegetable organisms are in some instances capable of changing their position and performing other movements. Thus the Zoospores of Cryptogamic plants are locomotive, and the Desmodium gyrans is possessed with a restless activity, its lateral leaflets dancing a perpetual measure to the music of the air. As we compare then these indications of sensibility, and these locomotive powers in the vegetable with the humbler endowments of such an animal as the sponge, which remains through life chained to one little spot of rock, giving out no indications of sensibility, we must at once be struck with the difficulties attending a true distinction, and the intimate relation that exists between the two kingdoms in question. True, we cannot instance the automatic performances of the vegetable as identical with the similar endowments of animal life, but still they indicate a sympathy, a harmony existing between the two organizations, and show us how closely the great principles of animal and vegetable life converge. Indeed, as they approach the common centre, the little cell that is the habitation of both, it is perhaps impossible to say, here begins animal and there vegetable life.[1] These, here in their infancy, are subtle essences far beyond our conception, and the naturalist, as he gathers this new world together on the field of his microscope, can only judge and name, after long and patient study of conformation and habits.
Thus far we have dealt in generalities, let us now therefore exa-
- ↑ This animal and vegetable affinity is very amusingly discussed at p. 448 of the April No. of the Dublin University Magazine 1957.—Ed.
