392 Kansas Academy of Science. 



of conclusions and force of suggestion are taken into account, was 

 the climax of the purely observational method of advancing knowl- 

 edge. It came at a time when biological thought was ripe for a 

 change of attitude and method of dealing with natural phenomena. 

 Its great author, together with other leaders in biology, passed al- 

 most wholly to experimentation in the discovery, demonstration 

 and confirmation of the principles underlying the action of the 

 constituency of the organic world. This method was used to the 

 fullest extent, first in physiological inquiry, in the calibration of 

 functional performances, and was later applied to ontogenetic de- 

 velopment and the intf^rpretation of form, so that now even the 

 taxonomic and phyletic generalization lean upon its results for 

 support. Genetics, descent and heredity escaped more slowly from 

 the domination of illusive speculations and dogmatic philosophy, 

 bufnow in these, as in practically all branches of human thought, 

 we are no longer content with casual and hazardous arrangements 

 of facts to fit preconceived theories, with unrestrained metaphysical 

 interpretations of nature, but demand progression by experience 

 and the foundation of generalizations concerning evolution upon 

 known causes, appreciable mechanisms, and movements of ascer- 

 tained direction. 



Extensive fields of research lie without the domain of experi- 

 mentation, yet the data gleaned from them must be put to the test 

 of comparison with results analytically obtained. In a direct study 

 of genetics we have at our command the pedigree culture; the con- 

 ception of unit characters; some facts and a practicable theory as 

 to the mechanism of heredity and the physical basis of inheritance; 

 a better knowledge of the nature and causes of variability, due to 

 the use of statistical methods, with a realization of the occurrence 

 and importance of mutations; the power of inducing certain de- 

 partures by the use of compounds or climatic factors; much evi- 

 dence, chiefly of a paleontological character, as to definiteness of 

 variations; a comprehension of the relations of environic factors to 

 germ-plasm and soma, and some important results in selection ob- 

 tained from breeding operations, together representing reasonable 

 progress in the advancement of knowledge of a subject, established 

 by Darwin, whose own work upon it remains its greatest contri- 

 bution. 



