Page:Insectivorous Plants, Darwin, 1899.djvu/13

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CONTENTS.




Drosera rotundifolia, or the Common Sun-dew.

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
Pages 1–17

The Movements of the Tentacles from the Contact of Solid Bones.

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 tentacles when their glands are excited by repeated touches—Falling drops of water do not cause inflection
18–32

Aggregation of the Protoplasm within the Cells of the Tentacles.

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 salts of ammonia—Of other substances, organic fluids, &c.—Of water—Of heat—Redissolution of the aggregated masses—Proximate causes of the aggregation of the protoplasm—Summary and concluding remarks—Supplementary observations on aggregation in the roots of plants