THE STORY OF NINETEENTH-CENTURY SCIENCE 



surroundings, such as altered climate, or the migration 

 into their territory of more masterful species. Past and 

 present causes are one natural law is changeless and 

 eternal. 



Such was the essence of the Huttonian doctrine, which 

 Lyell adopted and extended, and with which his name 

 will always be associated. Largely through his efforts, 

 though of course not without the aid of many other 

 workers after a time, this idea the doctrine of uniform- 

 itarianism, it came to be called became the accepted 

 dogma of the geologic world not long after the middle 

 of our century. The catastrophists, after clinging madly 

 to their phantom for a generation, at last capitulated 

 without terms: the old heresy became the new ortho- 

 doxy, and the way was paved for a fresh controversy. 



IV 



The fresh controversy followed quite as a matter of 

 course. For the idea of catastrophism had not con- 

 cerned the destruction of species merely, but their intro- 

 duction as well. If whole faunas had been extirpated 

 suddenly, new faunas had presumably been introduced 

 with equal suddenness by special creation ; but if species 

 die out gradually, the introduction of new species may 

 be presumed to be correspondingly gradual. Then may 

 not the new species of a later geological epoch be the 

 modified lineal descendants of the extinct population of 

 an earlier epoch ? 



The idea that such might be the case was not new. 

 It had been suggested when fossils first began to attract 

 conspicuous attention; and such sagacious thinkers as 

 Buffon and Kant and Goethe and Erasmus Darwin had 



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