ILLUSTRATIONS 



XXV 



FIG. 



72. 



73- 



74. 



75- 

 76. 



77- 



78. 



79- 

 80. 



81. 



82. 



83- 

 84. 



85. 

 86. 



87. 

 88. 

 89. 

 90. 

 91. 



92. 



93- 



94. 

 94a 



95- 

 96. 



97- 

 98. 



99. 

 100. 

 101. 

 102. 

 103. 

 104. 



PAGE 



The Earliest Known Picture of Cells, from Hooke's Micro- 



graphia (1665), 238 



Sketch from Malpighi's Treatise on the Anatomy of Plants 



(1670), 239 



Theodor Schwann, 1810-1882, 245 



M. Schleiden, 1 804-1 88 1, 246 



The Egg and Early Stages in Its Development (after Ge- 



genbaur), 253 



An Early Stage in the Development of the Egg of a Rock 



Limpet (after Conklin), 254 



Highly Magnified Tissue-Cells from the Skin of a Sala- 

 mander (after Wilson), 255 



Diagram of the Chief Steps in Cell-Division (after Parker), 256 

 Diagram of a Cell (modified after Wilson), . . .257 

 (A) Rotation of Protoplasm in Cells of Nitella. (B) High- 

 ly Magnified Cells of a Tradescantia Plant, Showing 

 Circulation of Protoplasm (after Sedgwick and Wilson), 261 



265 

 267 

 268 

 269 

 271 

 272 



273 

 280 



283 



290 



295 

 301 



302 



304 

 316 



319 

 333 



335 

 336 

 338 

 339 

 34i 

 354 

 355 



Felix Dujardin, 1801-1860, 



Purkinje, 1 787-1869, 



Carl Nageli, 1817-1891, . 



Hugo von Mohl, 1805-1872, 



Ferdinand Cohn, 1828-1898, 



Heinrich Anton De Bary, 1831-1888, 



Max Schultze, 1825-1874, 



Francesco Redi, 1 626-1697, 



Lazzaro Spallanzani, i 729-1 799, 



Apparatus of Tyndall for Experimenting on Spontaneous 



Generation, .... 

 Louis Pasteur (182 2-1 895) and His Granddaughter, 

 Robert Koch, 1843-1910, 

 Sir Joseph Lister, 1827-1912, 

 , Fritz Schaudinn, 1871-1906, 

 Gregor Mendel, 1822-1884, 

 Francis Galton, 1822-1911, 

 Charles Lyell, 1 797-1875, . 

 Professor Owen and the Extinct Fossil Bird of New 



land, .... 



Louis Agassiz, 1807-1873, 

 E. D. Cope, 1840-1897, 

 O. C. Marsh, 1831-1899, 

 Karl von Zittel, 1839-1904, 



Transmutations of Paludina (after Neumayer), 

 Planorbis Shells from Steinheim (after Hyatt), 



Zea 



