156 Controversial Questions. 



tion to a different climate and so forth affect the fluc- 

 tuating cliaracters of man to no small extent. But only 

 for a time; as soon as the disturbing factor is removed, 

 the effect which it produced disappears. The morpho- 

 logical characters of the race on the other hand are not 

 in the least affected by such influences. New varieties 

 do not arise by this means. Since the beginning of the 

 diluvial period man has not given rise to any new races 

 or types. He is, in fact, immutable, albeit highly variable. 



In order to attain to some insight into the causes and 

 significance of individual differences in man we must 

 study the corresponding differences which are presented 

 by an assemblage of forms belonging to a single species 

 of animal or plant. Here is a wide and fertile field open 

 for investigation ; but one in which the harvest of in- 

 formation has been poor so far. 



Ammon, as we have already said, is the most con- 

 siderable of the anthropological writers on this subject. 

 Although he does not distinguish between the theories of 

 selection and mutation, he sees clearly that our knowl- 

 edge of the origin of species in nature has no bearing 

 on social questions. And as it is on this point that most 

 sociological writers are in error it will be worth our 

 while to pa}^ some attention to his actual position.^ 



Ammon sets forth the modern theory of selection in 

 five theses of which the first four deal with heredity, 

 variability, the struggle for existence and elimination of 

 the unfit (Natiirliche Auslese).^ 



The fifth thesis deals with the theory of descent. It 

 runs : ''The forms and characters which, having arisen 



^ Otto Ammon, Die Gcsellschaftsordnung und Hire nafilrlichen 

 Grundlagcn, 2d edition, 1896, pp. 9-10. 



^This happy phrase of Ammon is eminently preferable to Natiir- 

 liche Zuchtwahl. 



