A DEFINITION OF EVOLUTION 



Figure 27. David Starr Jordan. 

 (From the Huntington Library.) 



thought that these were second-rate biologists who were bHnded by the 

 lorilhance of a great man: on the contrar\', they were excellent men in 

 their respective fields. Huxley made brilliant contributions to the develop- 

 ment of invertebrate zoology, taxonomy, and vertebrate anatomy. Spencer 

 was one of the leading philosophers of his time. Romanes began his career 

 as an invertebrate neuroloiiist, but he soon became exclusivelv eno;rossed 

 in evolutionary problems. Jordan (Figure 27) was undoubtedh' one of the 

 best ichthvoloirists who has ever lived. And Grav was a botanist of such 

 stature that his work still has ijreat influence. Nor must it be thought that 

 they never ventured to differ from Darwin, for these men were independ- 

 ent thinkers. Yet the atmosphere of approbation was extraordinary. 



It has been said that evolution was born in England, but found its home 

 in Germany. The German evolutionists of the Romantic P(^riod were more 

 strictlv Darwinian than their En<ilish and American colleagues in the 

 sense that they were generallv more thorough and careful collectors of 

 detailed data. The leaders in Germany were Carl Gegenbaur, Ernst 

 Ilaeckel, and August Weismann. Gegenbaur was a comparative anatomist, 

 and undoubtedly one of the greatest and most influential, for his students 

 held most of the chairs of anatomv in T'-uroiK^an unixcM'sities throughout 

 the Romantic Period. IJe and his collaborators made exhansti\'c studies, 

 in complete detail, upon all classes of vertebrates, and used the data so 

 obtained in support of Darwinian theorv. Much of [Uv phylogeny of [he 

 vertebrates, as represented in current textbooks of /oology, is taken from 

 the works of (iegenbaur and his collaborators. 



Ernst flaeckel did much less experimcMital work than did Gegenbaur, 

 yet he did do significant work in anatomy, cmbryolog) , and taxonomy. 



80 



