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WHAT position is to be assigned to Mr. DARWIN as a theorist, the future alone can determine; but as a patient and painstaking investigator of facts, he is without a peer. His Insectivorous Plants (D. Appleton and Co.) is a model of what such a book should be: in the previous preparation, over fifteen years of original study of the phenomena described; in the careful examination of these phenomena, exemplified by countless curious experiments; in the spirit of caution displayed in testing the facts and accepting the result to which they point; and in the clearness and simplicity of the descriptions.

The latter render the book fascinating to renders who are without any special scientific knowledge, but not without in interest in the curious and the romantic aspects of nature. The title of the book indicates the nature of the phenomena described—plants that live on insects, vegetable, carnivora, capturing, eating, and digesting animal food. The sun-dew is one of the most remarkable of these plants. It bears from two or three to five or six leaves, commonly a little broader than long. The whole upper surface is covered with gland-bearing filaments or tentacles, each leaf averaging about 200. The glands are surrounded by large drops of a viscid secretion. This secretion, Mr. Darwin is inclined to think, possesses an odor which attracts insects to the leaf. However this may be, they alight upon it in great numbers. They are caught by the viscid secretion- much as flies in a pot of molasses; the filaments then gradually bend over and clasp the insect on all sides. If the insect adheres to the glands of only a few of the exterior tentacles, these, bending over, carry their prey to the tentacles next succeeding them inward; these then bend forward, and so onward until the insect is ultimately carried by a curious sort of rolling movement to the centre of the leaf. All the tentacles then bend forward and inclose the prey. The secretion now not only increases in quantity, but becomes changed in quality. It becomes acid; it possesses the powers and performs the functions of gastric juice in the stomach; it has the power of dissolving animal matter, which is subsequently absorbed by, and senses the purpose of food for the plant.

Mr. Darwin tried repeated and successful experiments, feeding the hungry plant with bits of roast beef. He tried its digestive powers with various substances, noting carefully the result, and finding that as a general principle those substances which are indissoluble in the human stomach, such as human nails, hair, quills, oil, fat, etc., are equally indigestible to the plant. When the digestion is complete-a process which requires several days-the tentacles expand, the glands become temporarily dry, any useless remains are thus liable to be blown away by the wind, the glands begin again to secrete the liquid, and the tentacles are ready to seize a new prey. Quite as curious, in some respects even more so, is the action of the Venus fly-trap, found only in North Carolina. The leaf consists of two lobes standing at rather less than right angles to each other; they are armed with spikes, extending from the upper side of each lobe; these spikes stand in such a position that when the lobes close, they interlock like the teeth of a rat-trap. When an insect alights between the lobes of Wis leaf, the lobes immediately bend together at the top, the spikes interlock, the insect is captured; the lobes then press firmly against him, a juice answering to gastric juice is exuded, and the animal is eaten and digested much as in the case of the sun-dew. A very extraordinary fact is that a drop of liquid fulling upon the leaf produces no effect whenever; and while any disturbance from any other cause excites a movement of the leaf, any blowing upon it does not cause the slightest change in the lobes. Neither … nor wind is able to produce the action of the plant, which is endowed with a kind of substitute for intelligence in its power to discriminate between solid and liquid substances, without which it would be constantly opening and shutting its mouth to no purpose. These two illustrations of insectivorous plants may suffice to show the nature of the phenomena which Mr. Darwin has been investigating, but only a careful perusal of his book can give the reader any idea of the variety and interest of his curious experiments.