Relationship, significance of, 143.

Removal of waste, 39, 40.

Reproduction, 54, 80, 124, 148, 176;
—­rapidity of, 149.

Respiration, 37.

Reticulum of cell, 87;
—­of nucleus, 92.

Root tip, section of, 66.

S.

Schultze, 74, 75.

Schwann, 61, 62, 72.

Secretion, 39, 40.

Segmentation nucleus, 110.

Sensations, 46.

Separation of chromosomes, 100.

Sexual reproduction, 102.

Spermatozoan, 107, 109, 154.

Splitting of chromosomes, 99.

Spindle fibres, 101.

Struggle for existence, 168.

Summary of Part I, 128.

——­ general, 182.

U.

Undifferentiated protoplasm, 83.

Unicellular animals, 71.

Units of vital activity, 53.

Use and disuse, 171, 172.

V.

Variation, 148, 157, 160, 176.

Variation from sexual union, 162.

Variation in germ plasm, 161.

Vegetative functions, 41.

Villi, 31.

Vital force, vitality, 13, 15, 34, 37, 52, 80, 85.

Vital properties, 54;
—­located in cells, 123.

W.

Wing compared with arm, 144.

Wood cells, 68.

THE END.

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