1896.] on Ludicig and Modern Physiology. 13 



arose out of human suffering and the necessity of relieving it. It 

 sprang indeed out of Pathology. It was suffering that led us to 

 know, as regards our own bodies, that we had internal as well as 

 external organs ; and probably one of the first generalisations 

 which arose out of this knowledge was, that " if one member suffer 

 all the members suffer with it " — that all work together for the good 

 of the whole. In earlier times the good which was thus indicated 

 was associated in men's minds with human welfare exclusively. But 

 it was eventually seen that Nature has no less consideration for the 

 welfare of those of her products which to us seem hideous or mis- 

 chievous, than for those which we regard as most useful to man 

 or most deserving of his admiration. It thus became apj)arent that 

 the good in question could not be human exclusively, but as regards 

 each animal its own good — and that in the organised world the 

 existence and life of every sj^ecies is brought into subordination to 

 one purpose — its own success in the struggle for existence.* 



From what has preceded it may be readily understood that in 

 Physiology, Adaptation takes a more prominent part 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 working the end 

 of its existence, nothing further required to be said or known. 

 Physiologists of the present day recognise as fully as their pre- 

 decessors that perfection of contrivance which displays itself in all 

 living structures, the more exquisitely 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 attainment — how 

 she fashions as it were out of nothing and without 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 single example, referring 

 among its other perfections to the rapidity with which the eye can 

 be fixed on numerous objects in succession, and the instantaneous 

 and unconscious estimates which w^e are able to form of the distances 

 of objects, each estimate involving a process of arithmetic which no 



* I 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, insomuch 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 property of 

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

 evolutijn and descent are able to adapt themselves to their surroundings. It 

 is therefore only so far as organism (with all its attributes) is presupposed, that 

 the dependence of adaptation on survival is intelligible. 



