370 THE HISTORY AND SCOPE OF ZOOLOGY IX 



animals, as well as marine forms, alive and under 

 observation in conditions resembling as nearly as 

 possible those of nature, a step would have been taken 

 towards carrying on the study of Bionomics which 

 cannot long be delayed. It seems to be even more 

 important that the academic curriculum of Zoology 

 should not, by mere mechanical adhesion to the old 

 lines of Morphography, and experimental research on 

 the chemical and physical properties of tissues and 

 organs, confine the attention and training of young 

 students to what are now, comparatively speaking, 

 the less productive lines of research. 



If we turn to the other branch of Bionomics, that 

 concerned with the laws of variation and heredity 

 (Thremmatology), we find that since Darwin, and 

 independently of his own work, there has been a more 

 obvious progress than in Teleology. In the first place, 

 the continued study of human population has thrown 

 additional light on some of the questions involved, 

 whilst the progress of microscopical research in the 

 hands of Biitschli, Hertwig, Balfour, and August 

 Weismann promises to give us a clear foundation as 

 to the structural facts connected with the origin of 

 the egg-cell and sperm-cell and the process of fertilisa- 

 tion. This is not the fitting place in which to give a 

 sketch of the doctrines and hypotheses of Thremmat- 

 ology. They may be gathered from Darwin's writings, 

 more especially the Origin of Species and Animals 

 and Plants under Domestication. 1 They relate to 



1 The reader is also referred to Ribot's L'HJrdditd, and the writings 

 of Charles Darwin's cousin, Francis Galton. 



