Number of insects captured—Description of the leaves and their appendages or tentacles— Preliminary sketch of the action of the various parts, and of the manner in which insects are captured—Duration of the inflection of the tentacles—Nature of the secretion—Manner in which insects are carried to the centre of the leaf—Evidence that the glands have the power of absorption—Small size of the roots. During the summer of 1860, I was surprised by finding how large a number of insects were caught by t

Inflection of the exterior tentacles owing to the glands of the disc being excited by repeated touches, or by objects left in contact with them—Difference in the action of bodies yielding and not yielding soluble nitrogenous matter—Inflection of the exterior tentacles directly caused by objects left in contact with their glands—Periods of commencing inflection and of subsequent re-expansion—Extreme minuteness of the particles causing inflection—Action under water—Inflection of the exterior tenta

Nature of the contents of the cells before aggregation—Various causes which excite aggregation—The process commences within the glands and travels down the tentacles— Description of the aggregated masses and of their spontaneous movements—Currents of protoplasm along the walls of the cells—Action of carbonate of ammonia—The granules in the protoplasm which flows along the walls coalesce with the central masses—Minuteness of the quantity of carbonate of ammonia causing aggregation—Action of other

Nature of the experiments—Effects of boiling water—Warm water causes rapid inflection—Water at a higher temperature does not cause immediate inflection, but does not kill the leaves, as shown by their subsequent re-expansion and by the aggregation of the protoplasm—A still higher temperature kills the leaves and coagulates the albuminous contents of the glands. In my observations on Drosera rotundifolia, the leaves seemed to be more quickly inflected over animal substances, and to remain inflect

Non-nitrogenous fluids—Solutions of gum arabic—Sugar—Starch—Diluted alcohol—Olive oil— Infusion and decoction of tea—Nitrogenous fluids—Milk—Urine—Liquid albumen—Infusion of raw meat—Impure mucus—Saliva—Solution of isinglass—Difference in the action of these two sets of fluids—Decoction of green peas—Decoction and infusion of cabbage—Decoction of grass leaves. When, in 1860, I first observed Drosera, and was led to believe that the leaves absorbed nutritious matter from the insects which they ca

The secretion rendered acid by the direct and indirect excitement of the glands—Nature of the acid—Digestible substances—Albumen, its digestion arrested by alkalies, recommences by the addition of an acid—Meat—Fibrin—Syntonin—Areolar tissue—Cartilage—Fibro-cartilage— Bone—Enamel and dentine—Phosphate of lime—Fibrous basis of bone—Gelatine—Chondrin— Milk, casein and cheese—Gluten—Legumin—Pollen—Globulin—Haematin—Indigestible substances—Epidermic productions—Fibro-elastic tissue—Mucin—Pepsin—Urea—

Manner of performing the experiments—Action of distilled water in comparison with the solutions—Carbonate of ammonia, absorbed by the roots—The vapour absorbed by the glands—Drops on the disc—Minute drops applied to separate glands—Leaves immersed in weak solutions—Minuteness of the doses which induce aggregation of the protoplasm—Nitrate of ammonia, analogous experiments with—Phosphate of ammonia, analogous experiments with—Other salts of ammonia—Summary and concluding remarks on the action of

Salts of sodium, potassium, and other alkaline, earthy, and metallic salts—Summary on the action of these salts—Various acids—Summary on their action. Having found that the salts of ammonia were so powerful, I was led to investigate the action of some other salts. It will be convenient, first, to give a list of the substances tried (including forty-nine salts and two metallic acids), divided into two columns, showing those which cause inflection, and those which do not do so, or only doubtfully.

Strychnine, salts of—Quinine, sulphate of, does not soon arrest the movement of the protoplasm—Other salts of quinine—Digitaline—Nicotine—Atropine—Veratrine— Colchicine— Theine—Curare—Morphia—Hyoscyamus—Poison of the cobra, apparently accelerates the movements of the protoplasm—Camphor, a powerful stimulant, its vapour narcotic—Certain essential oils excite movement—Glycerine—Water and certain solutions retard or prevent the subsequent action of phosphate of ammonia—Alcohol innocuous, its vapour

Glands and summits of the tentacles alone sensitive—Transmission of the motor impulse down the pedicels of the tentacles, and across the blade of the leaf—Aggregation of the protoplasm, a reflex action—First discharge of the motor impulse sudden—Direction of the movements of the tentacles—Motor impulse transmitted through the cellular tissue— Mechanism of the movements—Nature of the motor impulse—Re-expansion of the tentacles. We have seen in the previous chapters that many widely different stim

As summaries have been given to most of the chapters, it will be sufficient here to recapitulate, as briefly as I can, the chief points. In the first chapter a preliminary sketch was given of the structure of the leaves, and of the manner in which they capture insects. This is effected by drops of extremely viscid fluid surrounding the glands and by the inward movement of the tentacles. As the plants gain most of their nutriment by this means, their roots are very poorly developed; and they ofte

Drosera anglica—Drosera intermedia—Drosera capensis—Drosera spathulata—Drosera filiformis—Drosera binata—Concluding remarks. I examined six other species of Drosera, some of them inhabitants of distant countries, chiefly for the sake of ascertaining whether they caught insects. This seemed the more necessary as the leaves of some of the species differ to an extraordinary degree in shape from the rounded ones of Drosera rotundifolia. In functional powers, however, they differ very little. [Droser

Structure of the leaves—Sensitiveness of the filaments—Rapid movement of the lobes caused by irritation of the filaments—Glands, their power of secretion—Slow movement caused by the absorption of animal matter—Evidence of absorption from the aggregated condition of the glands—Digestive power of the secretion—Action of chloroform, ether, and hydrocyanic acid—The manner in which insects are captured—Use of the marginal spikes—Kinds of insects captured—The transmission of the motor impulse and mech

Captures crustaceans—Structure of the leaves in comparison with those of Dionaea— Absorption by the glands, by the quadrifid processes, and points on the infolded margins— Aldrovanda vesiculosa, var. australis—Captures prey—Absorption of animal matter—Aldrovanda vesiculosa, var. verticillata—Concluding remarks. This plant may be called a miniature aquatic Dionaea. Stein discovered in 1873 that the bilobed leaves, which are generally found closed in Europe, open under a sufficiently high temperat

Drosophyllum—Structure of leaves—Nature of the secretion—Manner of catching insects— Power of absorption—Digestion of animal substances—Summary on Drosophyllum—Roridula—Byblis—Glandular hairs of other plants, their power of absorption—Saxifraga—Primula— Pelargonium—Erica—Mirabilis—Nicotiana—Summary on glandular hairs—Concluding remarks on the Droseraceae. Drosophyllum lusitanicum.—This rare plant has been found only in Portugal, and, as I hear from Dr. Hooker, in Morocco. I obtained living speci

Pinguicula vulgaris—Structure of leaves—Number of insects and other objects caught— Movement of the margins of the leaves—Uses of this movement—Secretion, digestion, and absorption—Action of the secretion on various animal and vegetable substances—The effects of substances not containing soluble nitrogenous matter on the glands—Pinguicula grandiflora—Pinguicula lusitanica, catches insects—Movement of the leaves, secretion and digestion. Pinguicula vulgaris.—This plant grows in moist places, gene

Utricularia neglecta—Structure of the bladder—The uses of the several parts—Number of imprisoned animals—Manner of capture—The bladders cannot digest animal matter, but absorb the products of its decay—Experiments on the absorption of certain fluids by the quadrifid processes—Absorption by the glands—Summary of the observation on absorption— Development of the bladders—Utricularia vulgaris—Utricularia minor—Utricularia clandestina. I was led to investigate the habits and structure of the species

Utricularia montana—Description of the bladders on the subterranean rhizomes—Prey captured by the bladders of plants under culture and in a state of nature—Absorption by the quadrifid processes and glands—Tubers serving as reservoirs for water—Various other species of Utricularia—Polypompholyx—Genlisea, different nature of the trap for capturing prey— Diversified methods by which plants are nourished. FIG. 26. (Utricularia montana.) Rhizome swollen into a tuber; the branches bearing minute bladd

It has now been shown that many species of Utricularia and of two closely allied genera, inhabiting the most distant parts of the world—Europe, Africa, India, the Malay Archipelago, Australia, North and South America—are admirably adapted for capturing by two methods small aquatic or terrestrial animals, and that they absorb the products of their decay. Ordinary plants of the higher classes procure the requisite inorganic elements from the soil by means of their roots, and absorb carbonic acid f