178 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



ness having been ascertained, there have now been discovered 

 real mechanical processes of adaptations also. They occur 

 among the statical tissues of plants, though not in that very 

 high degree which sometimes has been assumed to exist ; 

 they also occur in a very high perfection in the connective 

 tissue, in the muscles and in the bone tissue of vertebrates. 

 Here indeed it has proved possible to change the specific 

 structure of the tissue by changing the mechanical condi- 

 tions which were to be withstood, and it is in cases of heal- 

 ing of broken bones that these phenomena have acquired 

 a very great importance, both theoretically and practically : 

 the new joints also, which may arise by force of circumstances, 

 correspond mechanically to their newly created mechanical 

 function. 



So far a short review of the facts of " functionelle 

 Anpassung." They seem to prove that there does exist a 

 morphological adaptation to functional changes which result 

 from the very nature of functioning. In fact, the actual 

 state of all functioning tissue, the intensity of its state of 

 existence, if you care to say so, may be said to be due 

 to the functioning itself: the so-called atrophy by in- 

 activity being only one extreme of a very long line of 

 correspondences. 1 



We now, of course, have to ask ourselves if any more 

 intimate analysis of these facts is possible, and indeed we 

 easily discover that here also, as in the first of our groups of 

 morphological adaptations, there are always single definite 

 agents of the medium, which might be called " causes ' or 

 " means " of the adaptive effects, the word " medium '" being 



1 Atrophy of muscles by inactivity is not to be confused with atrophy by 

 cutting the motor nerve ; the latter is very much more complete. 



