198 DAEWINISM AND HUMAN LIFE 



We may speak of an organism as a bmidle of 

 adaptations, but we are not justified in saying that 

 every structure is an adaptation. There are some 

 structures whose use is unknown, and there are 

 others which seem to be of no value, such as well- 

 concealed decorativeness. It may be, however, 

 that some of the details whose significance is 

 unknown are the architectural correlates of im- 

 portant characters. 



Changes since Darwin's Day. — Darwin did not 

 doubt the legitimacy of supposing that some of 

 the direct effects of use and disuse and of the 

 influence of surroundings may be transmitted as 

 such or in a representative degree. He was, 

 therefore, to a Umited extent a Lamarckian, and 

 there are some competent authorities who occupy 

 a similar position. We are far from dogmatically 

 declaring that the Lamarckian position is quite 

 untenable, but we have hinted at some of the 

 difficulties which have led us to abandon it until 

 further evidence is forthcoming. 



Leaving this as a drawn battle, we wish to 

 refer briefly to two marked changes since Darwin's 

 day. In the first place, there has been a useful 

 attempt to give some experimental demonstration 

 of the working of natural selection. In the 

 second place, there is a growing feeling among 

 different bodies of workers that it is not necessary 

 to burden the shoulders of the natural selection 

 theory so heavily as heretofore. 



Evidences of Natural Selection. — One of 

 the most interesting — though, from the nature of 

 the case, least impressive — steps of progress since 

 Darwih's day is the attempt to secure definite 

 evidence of the operation of natural selection. 



