Insectivorous Plants

by the Classic British Author

Charles Darwin

Free Public Domain Book from the
Classic Literature Library

Insectivorous Plants Page 01

[page i] INSECTIVOROUS PLANTS.

[page ii.]

BY THE SAME AUTHOR.

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ON THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION; or, THE PRESERVATION OF FAVORED RACES IN THE STRUGGLE FOR LIFE. New and revised edition. 12mo. Cloth. 480 pages. Price, $2.00.

THE DESCENT OF MAN, AND SELECTION IN RELATION TO SEX. With Illustrations. New edition, revised and augmented. 12mo. Cloth. 704 pages. Price, $3.00.

A NATURALIST'S VOYAGE ROUND THE WORLD; or, A JOURNAL OF RESEARCHES INTO THE NATURAL HISTORY AND GEOLOGY OF THE COUNTRIES visited during the voyage of H.M.S. Beagle, under the command of Captain Fitz-Roy, R.N. 12mo. Cloth. 530 pages. Price, $2.00.

THE EXPRESSION OF THE EMOTIONS IN MAN AND ANIMALS. With Photographic and other Illustrations. 12mo. Cloth. Price, $3.00.

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THE THEORY OF DESCENT, AND DARWINISM. By Prof. OSCAR SCHMIDT, University of Strasburg. 12mo. Cloth. Price, $1.50.

[page iii.]

INSECTIVOROUS PLANTS

BY CHARLES DARWIN, M.A., F.R.S. ETC.

WITH ILLUSTRATIONS.

[page iv.]

[page v.]

CONTENTS.

CHAPTER I.

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 1-18

CHAPTER II.

THE MOVEMENTS OF THE TENTACLES FROM THE CONTACT OF SOLID BODIES.

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...19-37 [page vi.]

CHAPTER III.

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...Pages 38-65

CHAPTER IV.

THE EFFECTS OF HEAT ON THE LEAVES.

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...66-75

CHAPTER V.

THE EFFECTS OF NON-NITROGENOUS AND NITROGENOUS ORGANIC FLUIDS ON THE LEAVES.

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...76-84 [page vii.]

CHAPTER VI.

THE DIGESTIVE POWER OF THE SECRETION OF DROSERA.

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--Chitine-- Cellulose--Gun-cotton--Chlorophyll--Fat and oil--Starch--Action of the secretion on living seeds--Summary and concluding remarks...Pages 85-135

CHAPTER VII.

THE EFFECTS OF SALTS OF AMMONIA.

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 ammonia...136-173

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19th Century English Literature

Charles Darwin

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