26 Mutability and hidividual Variation, 



and in the passage cited in the Origin, he discusses the 

 question whether in Paleontology the immutability of 

 species was or was not assumed by the most prominent 

 workers.-^ 



The prevailing opinion was that individual variability 

 and mutability were two distinct phenomena. Variabil- 

 ity was well known both in cultivated and in wild species, 

 but most thoroughly in wild species which had been kept 

 in cultivation through a number of years. It was found 

 however to be limited, to depend upon the influence of the 

 environment and to be useful as a means of adaptation. 

 Mutability was not encountered in practical experience. 

 No cases of a species arising from another had occurred in 

 scientific cultures, nor were there any sufficiently authenti- 

 cated instances of the origin of new forms in the nursery 

 or the farm in spite of a thorough and critical scrutiny.^ 



The adherents of the Transmutation theory explained 

 the systematic relationship of the single forms (species, 

 varieties, and so forth) within the genera by the theory 

 that they had a common origin. The opponents of this 

 theory, in so far as they were upholders of the Linnean 

 conception of species, held exactly the same views, except 

 that they regarded the species as created and not the 

 genera. Foremost amongst them was Godron. who con- 

 sidered the races and varieties and even the species of 

 Jordan as having arisen from the Linnean species by 

 natural means, and made a very extensive collection of 

 facts and observations to prove this view. 



The third school was sharply opposed to these two 

 groups, the Transmutationists and the upholders of the 



^ Origin, p. xviii. 



^Jordan, De VOriginc des arhres fruiticrs, 1853, and Godron, De 

 I'cspcce et des races. 



