214 THE THEORY OF EVOLUTION 



The entire significance of the rudimentary gill in 

 this case would obviously consist therein that the Alpine 

 Salamander had become incapable of depositing its 

 young in water, as it formerly did. It remained, 

 however, despite this change, in every respect a true 

 Salamander in habit and also in the embryogeny, in 

 which only that was altered which could no longer serve. 



Regarding the origin of the Salamander, as member 

 of the Amphibia or Salamander type, the rudiment 

 says absolutely nothing ; its explanation as rudiment pre- 

 supposes rather the existence of the Alpine Salamander. 



(d) Rudiments now play an important role in the 

 theory of evolution, but mostly a very inglorious one. 

 Conscientious research must, however, in the first place 

 ascertain whether a rudiment really exists before 

 conclusions are come to. Wherever an actual function 

 can be determined, or some formation under consider- 

 ation cannot generally be regarded as an organ, but, 

 for instance, only as a necessary preliminary for the 

 fashioning of the adult form, then there is no question 

 of a rudiment. In the first case the actual function 

 fulfilled explains entirely the existence of that organ, 

 and no ground longer exists for seeking for another 

 earlier function, which the presence of that formation 

 should render comprehensible. 1 



In the second case it is precisely so. The organs 



1 For a long period it was the fashion to designate all formations, 

 whose function was unknown, straightway as rudiments. Ill this way 

 Wiedersheim has made a large collection of rudiments in man. See, for 

 instance, E. Wasmann : Biologie, etc., p. 454, and Kampf urn das Entwickl- 

 ungsproblem, p. 94. 



