INDEX AND GLOSSARY 



147 



S 



SACHS, on cells, 114 ; on re- 

 action and protoplasm, 133. 



Salix purpurea, reproduction 

 from galls, 51. 



SCHMITT, bone-grafting, 74. 



Segmentation, the early divi- 

 sion of a developing egg, 

 xvii. 



Segmentation spheres, the cells 

 resulting from the early di- 

 visions of a developing egg 



separation of, by Wilson and 

 Driesch, 60. 

 Segmentation cavity. See 



Blastosphere. 

 Sex, determination of, by 



temperature, 123, 124. 

 Sexual cells (spermatozoa in 

 male, ova or egg-cells in 

 female), the nucleated pieces 

 of protoplasm which are the 

 starting-point of the new 

 generation in sexual repro- 

 duction, origin of, 18. 

 Soma, the body of a plant or 

 animal as contrasted with 

 the reproductive cells con- 

 tained within it, 45. 

 Somatic cells, the cells of the 



soma ; mortality of, 17. 

 SPENCER, HERBERT, contro- 

 versy withWeismann on poly- 

 morphism in insects, 125. 

 Spermatogenesis,the formation 

 of spermatozoa in the testis, 

 13. 



Spontaneous generation, 2. 

 Stolon, a strand of tissue con- 

 necting the individuals of 

 colonial animals, 46. 

 STRASBURGER, the value of the 

 nucleus in heredity, 13, 18. 



T 



Termites, polymorphism in, 

 125. 



Transfusion of blood, 75. 



Transplantation of bone, 73, 

 74. 



TREMBLEY, grafting of Hydra, 

 72. 



Triton, an amphibian, experi- 

 ments on the egg by con- 

 striction, 64. 



Tubularia, experimental hetero- 

 morphoses, 51. 



Tuiiicata, a group of marine 

 animals clad with a leathery 

 tunic, 14. 



U 



Unicellular organisms, animals 

 (protozoa) and plants (proto- 

 phyta) with the simplest 

 structure, each being a single 

 ceU : immortality of, 17 ; 

 division doubling in, 40. 



Unit, definition of a biological, 

 30. 



Vegetative affinity, 66 et seq. 



Vertebrates, regeneration of 

 lost parts, 47. 



VOECHTIXG, experiments on 

 grafting, 70 ; harmonic and 

 disharmoiiic union, 70 ; on 

 cells, 114, 116 ; on plasticity 

 of plants, 117, 119 ; on 

 grafting, 120. 



W 



WEISMANN and preforrnation, 

 8-10 ; caution against experi- 

 ment, 12 ; sources of his 

 theory, 20, 21; Hertwig' 

 description of his theory, 22 



