22 READINGS IN EVOLUTION, GENETICS, AND EUGENICS 



the doctrine of Buffon, that the direct action of the environment was 

 the sole cause of evolution. He also, in a sense, anticipated De Vries, 

 in that he believed that new species might be formed by transmutation 

 or sudden large variations occurring in one generation. "Hence the 

 underlying causes of transformations," he said, "were profound 

 changes induced in the egg by external influences, accidents as it were, 

 regulated by law. " The controversy between Cuvier and St. Hilaire 

 was a losing one for the latter. The cards were stacked against him 

 and after him the evolution idea was retired to comparative obscurity 

 until revived by Charles Darwin. 



CATASTROPHISM AND UNIFORMITARIANISM 



The development of the science of geology had a profound influence 

 upon that of evolution. The prevailing theories as to historical 

 geology during the Middle Ages involved the idea of "catastrophism. " 

 According to this view all important changes in the earth's crust 

 represented sudden radical transformations, involving earthquakes, 

 volcanic outbursts, floods, sudden upliftings of submerged areas, or 

 equally sudden submergence of land bodies. From these ideas natu- 

 rally grew the related idea of great, world- wide destructions of animals 

 and plants, followed by re-creation of new faunas and floras. Cuvier, 

 for example, interpreted the more or less distinct fossil strata as being 

 the result of a series of tremendous cataclysms, the last of which had 

 been the great deluge of Scripture, in which Noah figured prominently. 

 He thought that at each cataclysm great floods of water had covered 

 the earth, that the existing animals had been buried in mud and thus 

 preserved as fossils, and that a new creation followed each cataclysm. 

 The great strength of this conception was that it appeared to give 

 scientific support to both special creation and the Mosaic account of 

 the "Flood." As compared with the pure evolutionary conception, 

 this alternative was highly acceptable to the church and was pro- 

 claimed as orthodox. The Scotch philosopher and geologist, Hutton, 

 who lived during the last half of the eighteenth century, combated the 

 idea of catastrophism by advocating the doctrine of "uniformitari- 

 anism," a view involving the idea that past changes on the earth 

 were the result of the same sort of gradual changes as are observed 

 to be taking place today in brief, that there has been a strict uni- 

 formity of change throughout the entire period of geologic history. 

 There may have been, according to this view, local catastrophes, 



