48 BIOLOGICAL SOCIETY OF WASHINGTON. 



terious manner, been each "created" separately; but how, few 

 ventured to express in words, for the mere attempt to do so con- 

 jured up such strange fancies that the intelligent mind drew back in 

 revolt and refused to consider them. Now, it is a recognized 

 scientific creed that the animals and plants which have successively 

 inhabited the earth, were the descendants, with modification, 

 from previous inhabitants since the dawn of life. A glimmer of 

 the truth had now and then occurred to contemplative students. 

 Philosophers had ventured to think that living forms like ancient 

 ones might have descended from them. The investigators in 

 various departments of biology had gradually deduced generaliza- 

 tions which all tended in a similar direction. The taxologists, in 

 their very nomenclature, compared the animal kingdom to a tree of 

 which the principal types were "branches" diverging from a com- 

 mon trunk, while the minor groups were successive offshoots ; and 

 the idea of genetic relationship suggested by the various degrees of 

 likeness was expressed in the names conferred on other groups — 

 "tribe," "family," etc. The embryologists had recognized a co- 

 incidence between the stages of development of the "superior" 

 animals and the adults of animals inferior in the system. The 

 palaeontologists had discovered an approximate coincidence between 

 the successive inhabitants of the earth and the successive stages in 

 the development of the living animals of the same types. The 

 series of facts thus obtained had even, to some extent, been co- 

 ordinated. 



All these series of facts were such as would have been the result 

 of the derivation of existing types from previous ones. But the 

 possibility that the seeming was the real did not commend itself to 

 the consideration of naturalists. Instead thereof, it was assumed 

 that the facts were " in accordance with a plan of the Creator; " 

 that the Deity had conceived a few patterns, and that by those he 

 constructed the animals which successively appeared on the globe, 

 to be in time swept off and replaced by others. If answer was 

 made that such was a puerile conception of creation and that it lim- 



