4 SCIENCE PROGRESS. 



the welfare of those of her products which to us seem 

 hideous or mischievous, than for those which we regard 

 as most useful to man or most deserving of his admiration. 

 It thus became apparent that the good in question could not 

 be human exclusively, but as regards each animal its oivn 

 good — and that in the organised world the existence and 

 life of every species is brought into subordination to one 

 purpose — its own success in the struggle for existence. 1 



From what has preceded it may be readily understood 

 that in Physiology, Adaptation takes a more prominent 

 place than Evolution or Descent. In the prescientific 

 period adaptation was everything. The observation that 

 any structure or arrangement exhibited marks of adaptation 

 to a useful purpose was accepted not merely as a guide in 

 research, but as a full and final explanation. Of an organism 

 or organ which perfectly fulfilled, in its structure and work- 

 ing, the end of its existence, nothing further required to be 

 said or known. Physiologists of the present day recognise 

 as fully as their predecessors that perfection of contrivance 

 which displays itself in all living structures, the more ex- 

 quisitely the more minutely they are examined. No one, 

 for example, has written more emphatically on this point 

 than did Ludwig. In one of his discourses, after showing 

 how Nature exceeds the highest standard of human attain- 

 ment — how she fashions as it were out of nothing and with- 

 out tools, instruments of a perfection which the human 

 artificer cannot reach, though provided with every suitable 

 material — wood, brass, glass, india-rubber — he gives the 

 organ of sight as a signal example, referring among its 



1 1 am aware that in thus stating the relation between adaptation and the 

 struggle for existence, I may seem to be reversing the order followed by 

 Mr. Darwin, inasmuch as he regarded the survival of organisms which are 

 fittest for their place in Nature, and of parts which are fittest for their 

 place in the organism, as the agency by which adaptedness is brought about. 

 However this may be expressed it cannot be doubted that fitness is an 

 essential of organisms. Living beings are the only things in Nature which 

 by virtue of evolution and descent are able to adapt themselves to their 

 surroundings. It is therefore only so far as organism (with all its attri- 

 butes) is presupposed, that the dependence of adaptation on survival is 

 intelligible. 



