EPILOGUE 778
INDEX 780
LIST OF ILLUSTRATIONS
1. Nerve-cells, from larger and smaller animals (Minot, after Irving Hardesty) . . . 37
2. Relative magnitudes of some minute organisms (Zsigmondy) . . . 39
3. Curves of growth in man (Quetelet and Bowditch) . . . 61
4, 5. Mean annual increments of stature and weight in man (do.) . . . 66, 69
6. The ratio, throughout life, of female weight to male (do.) . . . 71
7–9. Curves of growth of child, before and after birth (His and Rüssow) . . . 74–6
10. Curve of growth of bamboo (Ostwald, after Kraus) . . . 77
11. Coefficients of variability in human stature (Boas and Wissler) . . . 80
12. Growth in weight of mouse (Wolfgang Ostwald) . . . 83
13. Do. of silkworm (Luciani and Lo Monaco) . . . 84
14. Do. of tadpole (Ostwald, after Schaper) . . . 85
15. Larval eels, or Leptocephali, and young elver (Joh. Schmidt) . . . 86
16. Growth in length of Spirogyra (Hofmeister) . . . 87
17. Pulsations of growth in Crocus (Bose) . . . 88
18. Relative growth of brain, heart and body of man (Quetelet) . . . 90
19. Ratio of stature to span of arms (do.) . . . 94
20. Rates of growth near the tip of a bean-root (Sachs) . . . 96
21, 22. The weight-length ratio of the plaice, and its annual periodic changes . . . 99, 100
23. Variability of tail-forceps in earwigs (Bateson) . . . 104
24. Variability of body-length in plaice . . . 105
25. Rate of growth in plants in relation to temperature (Sachs) . . . 109
26. Do. in maize, observed (Köppen), and calculated curves . . . 112
27. Do. in roots of peas (Miss I. Leitch) . . . 113
28, 29. Rate of growth of frog in relation to temperature (Jenkinson, after O. Hertwig), and calculated curves of do. . . . 115, 6
30. Seasonal fluctuation of rate of growth in man (Daffner) . . . 119
31. Do. in the rate of growth of trees (C. E. Hall) . . . 120
32. Long-period fluctuation in the rate of growth of Arizona trees (A. E. Douglass) . . . 122
33, 34. The varying form of brine-shrimps (Artemia), in relation to salinity (Abonyi) . . . 128, 9
35–39. Curves of regenerative growth in tadpoles’ tails (M. L. Durbin) . . . 140–145
40. Relation between amount of tail removed, amount restored, and time required for restoration (M. M. Ellis) . . . 148
41. Caryokinesis in trout’s egg (Prenant, after Prof. P. Bouin) . . . 169
42–51. Diagrams of mitotic cell-division (Prof. E. B. Wilson) . . . 171–5
52. Chromosomes in course of splitting and separation (Hatschek and Flemming) . . . 180
53. Annular chromosomes of mole-cricket (Wilson, after vom Rath) . . . 181
54–56. Diagrams illustrating a hypothetic field of force in caryokinesis (Prof. W. Peddie) . . . 182–4
57. An artificial figure of caryokinesis (Leduc) . . . 186
58. A segmented egg of Cerebratulus (Prenant, after Coe) . . . 189
59. Diagram of a field of force with two like poles . . . 189
60. A budding yeast-cell . . . 213
61. The roulettes of the conic sections . . . 218
62. Mode of development of an unduloid from a cylindrical tube . . . 220
63–65. Cylindrical, unduloid, nodoid and catenoid oil-globules (Plateau) . . . 222, 3
66. Diagram of the nodoid, or elastic curve . . . 224
67. Diagram of a cylinder capped by the corresponding portion of a sphere . . . 226
68. A liquid cylinder breaking up into spheres . . . 227
69. The same phenomenon in a protoplasmic cell of Trianea . . . 234
70. Some phases of a splash (A. M. Worthington) . . . 235
71. A breaking wave (do.) . . . 236
72. The calycles of some campanularian zoophytes . . . 237
73. A flagellate monad, Distigma proteus (Saville Kent) . . . 246
74. Noctiluca miliaris, diagrammatic . . . 246
75. Various species of Vorticella (Saville Kent and others) . . . 247
76. Various species of Salpingoeca (do.) . . . 248
77. Species of Tintinnus, Dinobryon and Codonella (do.) . . . 248
78. The tube or cup of Vaginicola . . . 248
79. The same of Folliculina . . . 249
80. Trachelophyllum (Wreszniowski) . . . 249
81. Trichodina pediculus . . . 252
82. Dinenymplia gracilis (Leidy) . . . 253
83. A “collar-cell” of Codosiga . . . 254
84. Various species of Lagena (Brady) . . . 256
85. Hanging drops, to illustrate the unduloid form (C. R. Darling) . . . 257
86. Diagram of a fluted cylinder . . . 260
87. Nodosaria scalaris (Brady) . . . 262
88. Fluted and pleated gonangia of certain Campanularians (Allman) . . . 262
89. Various species of Nodosaria, Sagrina and Rheophax (Brady) . . . 263
90. Trypanosoma tineae and Spirochaeta anodontae, to shew undulating membranes (Minchin and Fantham) . . . 266
91. Some species of Trichomastix and Trichomonas (Kofoid) . . . 267
92. Herpetomonas assuming the undulatory membrane of a Trypanosome (D. L. Mackinnon) . . . 268
93. Diagram of a human blood-corpuscle . . . 271
94. Sperm-cells of decapod crustacea, Inachus and Galathea (Koltzoff) . . . 273
95. The same, in saline solutions of varying density (do.) . . . 274
96. A sperm-cell of Dromia (do.) . . . 275
97. Chondriosomes in cells of kidney and pancreas (Barratt and Mathews) . . . 285
98. Adsorptive concentration of potassium salts in various plant-cells (Macallum) . . . 290
99–101. Equilibrium of surface-tension in a floating drop . . . 294, 5
102. Plateau’s “bourrelet” in plant-cells; diagrammatic (Berthold) . . . 298
103. Parenchyma of maize, shewing the same phenomenon . . . 298
104, 5. Diagrams of the partition-wall between two soap-bubbles . . . 299, 300
106. Diagram of a partition in a conical cell . . . 300
107. Chains of cells in Nostoc, Anabaena and other low algae . . . 300
108. Diagram of a symmetrically divided soap-bubble . . . 301
109. Arrangement of partitions in dividing spores of Pellia (Campbell) . . . 302
110. Cells of Dictyota (Reinke) . . . 303
111, 2. Terminal and other cells of Chara, and young antheridium of do. . . . 303
113. Diagram of cell-walls and partitions under various conditions of tension . . . 304
114, 5. The partition-surfaces of three interconnected bubbles . . . 307, 8
116. Diagram of four interconnected cells or bubbles . . . 309
117. Various configurations of four cells in a frog’s egg (Rauber) . . . 311
118. Another diagram of two conjoined soap-bubbles . . . 313
119. A froth of bubbles, shewing its outer or “epidermal” layer . . . 314
120. A tetrahedron, or tetrahedral system, shewing its centre of symmetry . . . 317
121. A group of hexagonal cells (Bonanni) . . . 319
122, 3. Artificial cellular tissues (Leduc) . . . 320
124. Epidermis of Girardia (Goebel) . . . 321
125. Soap-froth, and the same under compression (Rhumbler) . . . 322
126. Epidermal cells of Elodea canadensis (Berthold) . . . 322
127. Lithostrotion Martini (Nicholson) . . . 325
128. Cyathophyllum hexagonum (Nicholson, after Zittel) . . . 325
129. Arachnophyllum pentagonum (Nicholson) . . . 326
130. Heliolites (Woods) . . . 326
131. Confluent septa in Thamnastraea and Comoseris (Nicholson, after Zittel) . . . 327
132. Geometrical construction of a bee’s cell . . . 330
133. Stellate cells in the pith of a rush; diagrammatic . . . 335
134. Diagram of soap-films formed in a cubical wire skeleton (Plateau) . . . 337
135. Polar furrows in systems of four soap-bubbles (Robert) . . . 341
136–8. Diagrams illustrating the division of a cube by partitions of minimal area . . . 347–50
139. Cells from hairs of Sphacelaria (Berthold) . . . 351
140. The bisection of an isosceles triangle by minimal partitions . . . 353
141. The similar partitioning of spheroidal and conical cells . . . 353
142. S-shaped partitions from cells of algae and mosses (Reinke and others) . . . 355
143. Diagrammatic explanation of the S-shaped partitions . . . 356
144. Development of Erythrotrichia (Berthold) . . . 359
145. Periclinal, anticlinal and radial partitioning of a quadrant . . . 359
146. Construction for the minimal partitioning of a quadrant . . . 361
147. Another diagram of anticlinal and periclinal partitions . . . 362
148. Mode of segmentation of an artificially flattened frog’s egg (Roux) . . . 363
149. The bisection, by minimal partitions, of a prism of small angle . . . 364
150. Comparative diagram of the various modes of bisection of a prismatic sector . . . 365
151. Diagram of the further growth of the two halves of a quadrantal cell . . . 367
152. Diagram of the origin of an epidermic layer of cells . . . 370
153. A discoidal cell dividing into octants . . . 371
154. A germinating spore of Riccia (after Campbell), to shew the manner of space-partitioning in the cellular tissue . . . 372
155, 6. Theoretical arrangement of successive partitions in a discoidal cell . . . 373
157. Sections of a moss-embryo (Kienitz-Gerloff) . . . 374
158. Various possible arrangements of partitions in groups of four to eight cells . . . 375
159. Three modes of partitioning in a system of six cells . . . 376
160, 1. Segmenting eggs of Trochus (Robert), and of Cynthia (Conklin) . . . 377
162. Section of the apical cone of Salvinia (Pringsheim) . . . 377
163, 4. Segmenting eggs of Pyrosoma (Korotneff), and of Echinus (Driesch) . . . 377
165. Segmenting egg of a cephalopod (Watase) . . . 378