De Vries (1889). Pangenes produced by nucleus. 

 Summary. 



8. Idioplasm and trophoplasm, 



Nageli (1884). Idioplasm the truly living sub- 

 stance, trophoplasm its nutritive matrix. 



Weismann (1885). Idioplasm restricted to the 

 nucleus, and distinguished from cytoplasm. 



Andrews (1897). Continuous and discontinuous 

 substance. 



9. Somatic idioplasm and germplasm. 



Weismann (1883, 1885, 1893). Germplasm dis- 

 tinguished from somatic idioplasm. 



MiNOT (1896). Panplasm. 



10. The nucleus as the seat of the germplasm. 



O. Hertwig (1875). Fusion of nuclei during fer- 

 tilization of the egg. 



Van Beneden (1883). Equal number of chromo- 

 somes in male and female pronuclei. 



Strasburger (1884). Same process in plants. 



GuiGNARD (1891). Fertilization in the lily. 

 Later observations on fertilization. 



BovERi (1887), Hertwig (1890). Maturation. 



Pfluger (1883). Isotropism of the egg. 



Hertwig (1884). Position of the spindle deter- 

 mines the plane of cleavage. 



Brandt (1877), Nussbaum (1884). Enucleated 

 fragments. 



Verworn, Lillie. Dependence of nucleus upon 

 cytoplasm. 



