INDEX 



235 



Sewertzoff, A. N., 3 



Sex reversal, 103 



Sexual selection, 70, 114 



Simocephalus vetulus, 157 



Skinner, H., 42 



Smith, E. A., 155, 222, 223 



Smith, John B., 42 



Snakes, garter, 161 



Social organization, 20 



Soma, 87, 90, 209 



Specialization, 90 



Speciation, 161 



Species, 22, 26, 39; change in, 

 68; elementary, 27; and indi- 

 vidual, 29, 135; instability of, 

 33; Lotsy's, 129; reality of, 

 29; and reproduction, 105; 

 scope of, 44; uniformity of, 

 181 



Spencer, W. P., 102 



Spermatozoa, 80, 91 



Spontaneous generation, 14 



Stature, 67 



Stimulus, 224 



Subspecies, 69 



Sumner, F. B., 60, Q6, 73, 148, 

 153, 156 



Survival of the fittest, 71 



Symbiosis, 20 



Taenia solium, 37 



Temperature, 36, 56, 89; effect 

 on mice, 60; regulation, 21 



Tetrakinetic theory, 55 



Theories: centro-epigenesis, 139; 

 coincident selection, 116; ger- 

 minal selection, 115; intra- 

 selection, 116; isolation, 119; 

 kinetogenesis, 138; Lamarck- 



ian, 127; mneme, 139; muta- 

 tion, 127; orthogenesis, 131; 

 pangenesis, 139; panmixia, 

 115; parallel induction, 140; 

 preadaptation, 125, 133; re- 

 capitulation, 167; tetrakinetic, 

 55; use and disuse in chro- 

 mosomes, 208 



Thinking, 183 



Thyroid, 37, 65, 181 



Translocation, 170 



Transplantation, 38 



Tree hoppers, 61 



Troland, L. T., 81, 97 



Tropisms, 188, 196 



Trout, 152 



Tulips, 74 



Typhoid, 223 



Unit characters, 40 



Uranium, 48 



Use and disuse, 137; results of, 



56 

 Usefulness, 70 



Variation, cause of, 53; of en- 

 vironment, 49; geographic, 42; 

 of heritage, 49, 52; seasonal, 

 41 



Varieties, 69; of C, macilentus, 

 70 



Vertebrates, terrestrial, 218 



Vitalists, 108 



Vitamines, 65 



Wagner, A., 110 

 Wagner, M., 119 

 Water, 36, 50 



Weismann, A., 92, 103, 115, 125, 

 209 



