216 



INDEX 



Virchow, 69; biographical refer- 

 ences to, 202 



Virus, 137 



Vries, Hugo, de, 159-160; muta- 

 tion theory of, 160; portrait, 156 



W 



Wallace, A. R., and Darwin, 153, 



154 



Weismann, 154; biographical ref- 

 erences to, 202; a nee-Darwin- 

 ian, 154; portrait, 156; his 

 theory of heredity, 154, 155; 

 of evolution, 156, outstanding 

 features of, 159 



Whitman, C. O., biographical 

 references to, 202; influence on 

 biology, 119; portrait, 96 



Yellow Fever, cause of, 135; the 

 Commission of, 136; trans- 

 mitted by mosquitoes, 137; 

 Walter Weed and, 136 



Zittel, and paleontology, 96 



Zoology, adjuncts to the study of, 

 123; aspects of, 3, 5; a subject 

 of general education, 1-8; as a 

 unified science, iv, 2; basal to 

 the study of medicine, 7; books 

 about, 191-208; the central 

 subject of biology, i, 6; emerges, 

 43-51; experimental, 113; the 

 foremost men of, 174-180; of 

 fossil remains, 95-105; greatest 

 present activity in, 121, 122; 

 and intellectual progress, 185- 

 187; the maul currents of, 4, 5, 

 9; main pathways of, 106-120; 

 miscellaneous divisions of, 116; 

 philosophical, 115; its position 

 in biology, 6; recent tendencies 

 of, 121-123; structural, 147 



Zoological Progress, a system of 

 thought, iii 



Zoological Thought, continuity 

 of, 4 





