336 Appendix A 



the adult would change correspondingly ; and these changes 

 would be so profound that in many cases it would appear as 

 if the constitution, or stirp, had also changed. Illustrations 

 might be given of changes of the most profound character 

 induced by changes in either of the above factors of environ- 

 ment, and in the case of the motor factor or animal motion 

 the habits of the animal would, in the course of a lifetime, 

 profoundly modify its structure. For example, if the human 

 infant were brought up in the branches of a tree as an arboreal 

 type, instead of as a terrestrial, bi-pedal type, there is little 

 doubt that some of the well-known early adaptations to arboreal 

 habit (such as the turning in of the soles of the feet, and the 

 grasping of the hands) might be retained and cultivated ; thus 

 a profoundly different type of man would be produced. Similar 

 changes in the action of environment are constantly in progress 

 in nature, since there is no doubt that the changes of environ- 

 ment and the habits which it so brings about far outstrip 

 all changes in constitution. This fact, which has not been 

 sufficiently emphasized before, offers an explanation of the 

 evidence advanced by Cope and other writers that change in 

 the forms of the skeletons of the vertebrates first appears in 

 ontogeny and subsequently in phylogeny. During the enor- 

 mously long period of time in which habits induce ontogenic 

 variations, it is possible for natural selection to work very 

 slowly and gradually upon predispositions to useful correlated 

 variations, and thus what are primarily ontogenic variations 

 become slowly apparent as phylogenic variations or congenital 

 characters of the race. Man, for instance, has been upon the 

 earth perhaps seventy thousand years ; natural selection has 

 been slowly operating upon certain of these predispositions, 

 but has not yet eliminated those traces of the human arboreal 

 habits, nor completely adapted the human frame to the upright 

 position. This is as much an expression of habit and ontogenic 

 variation as it is a constitutional character. Very similar views 

 were expressed to the speaker in a conversation recently held 

 with Professor Lloyd Morgan, and it appears as if a similar 

 conclusion had been arrived at independently. Professor 



