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PAGE 
theory, 250. The cell-theory becomes harmonized with the pro- 
toplasm doctrine of Max Schultze, 251. Further modifications of 
the cell-theory, 252. Origin of cells in tissues, 252. Structure of 
the nucleus, 253. Chromosomes, 254. Centrosome, 256. The 
principles of heredity as related to cellular studies, 257. Ver- 
worn’s definition, 258. Vast importance of the cell-theory in 
advancing biology, 258. 
CHAPTER NII 
PROTOPLASM THE PHysicaL Basis oF LIFE, ; ? : : 259 
Great influence of the protoplasm doctrine on biological progress, 2509. 
Protoplasm, 259. Its properties as discovered by examination of 
the ameeba, 260. Microscopic examination of a transparent leaf, 
261. Unceasing activity of its protoplasm, 261. The wonderful 
energies of protoplasm, 261. Quotation from Huxley, 262. The 
discovery of protoplasm and the essential steps in recognizing 
the part it plays in living beings, 262-275. Dujardin, 262. His 
personality, 263. Education, 263. His contributions to science, 
264. His discovery of “‘sarcode”’ in the simplest animals, in 1835, 
266. Purkinje, in 1840, uses the term protoplasma, 267. Von 
Mohl, in 1846, brings the designation protoplasm into general 
use, 268. Cohn, in 1850, maintains the identity of sarcode and 
protoplasm, 270. Work of De Bary and Virchow, 272. Max 
Schultze, in 1861, shows that there is u broad likeness between 
the protoplasm of animals and plants, and establishes the proto- 
plasm doctrine. The university life of Schultze. His love of 
music and science. Founds a famous biological periodical, 272- 
274. The period from 1840 to 1860 an important one for biol- 
OBy, 274. 
CHAPTER NIII 
THE WorK oF PasTEuR, Kocu, AND OTHERS, : i ( - 276 
The bacteria discovered by Leeuwenhoek in 1687, 276. The develop- 
ment of the science of bacteriology of great importance to the 
human race, 276. Some general topics connected with the study 
of bacteria, 277. The spontaneous origin of life, 277-293. Bio- 
genesis or abiogenesis, 277. Historical development of the ques- 
tion, 277. I. From Aristotle, 325 B.c., to Redi, 1668, 278. The 
spontaneous origin of living forms universally believed in, 278. 
Illustrations, 278. II. From Redi to Schwann, 278-284. Redi, 
