Descent of Man 313 



conditions, to all its rivals of older ancestry, and superior to 

 any possible development of old ancestry. It is not only 

 possible but highly probable, therefore that humanity arose 

 in such a series, of late or comparatively new creation, of 

 which few members survived, and of which the survivors 

 all merged, and which is related to the other mammalians 

 only through a lost species of most primitive type antedating 

 most existing forms. This would help to account for man's 

 isolation in the animal world; and although it is not, in 

 present light, to be proved, it is possible enough to justify 

 the repugnance instinctively felt toward brute life, when 

 close relationship is urged by a precipitant philosophy. 

 There is every indication that types present resemblances, 

 not only because of actual racial connection, but because 

 of recurrence of similar conditions, which, in the same life 

 substance, cause similar results. 



The time involved in the process of evolution being un- 

 limited, and without definite end, is seen to be productive of 

 changes equally unlimited and indefinite. After types of 

 structure have been established in certain systems and with 

 certain features, the activity in response to environment has 

 proceeded in a secondary phase of modifying effect, to 

 specialize the features but with less creative energy. It is 

 to be supposed that common and general forms of struc- 

 ture arise as a natural outcome of the life energy, in re- 

 action of certain elements to a given position in certain 

 environments. The vertebrate structure for example is 

 apparently a necessary result of a skeleton building habit 

 newly acquired in a nerve threaded body, and with the same 

 materials, available in similar conditions, it is to be believed 



