56 The Universe and Life 



individuals, nothing is more striking than the great 

 numbers of imperfect, unadapted individuals that are 

 produced. Whether we study thus the infusorian, the 

 fruit fly, or man, we find produced misshapen crea- 

 tures, weak creatures, individuals that lack essential 

 organs, individuals whose senses are imperfect or who 

 lack certain sense organs ; individuals whose internal 

 organs work but ill, whose intimate chemical processes 

 are imperfect ; individuals whose nervous systems fail 

 to provide guidance. And the imperfections, it is 

 found, are in the essential constitution of the crea- 

 tures, for in so far as they reproduce, they bring forth 

 anew imperfect offspring like themselves. Types that 

 are weak, imperfect, incapable of continued life are 

 started with the same profusion as are the efficient, 

 adapted types; in fact, in a hundred times greater 

 profusion. Students of genetics find that most of the 

 new races begun by mutations in the hereditary con- 

 stitution are of these imperfect types. Such defective, 

 unadaptive types soon die out, some without repro- 

 ducing at all and leaving no record; others after a 

 few generations. Some persist for a time, to found a 

 weak type or species that eventually disappears. The 

 pathway of developing life is profusely marked with 

 these imperfect starts, with the attempts of life to 

 move in directions that lead but to conditions in which 

 life is impossible. This is something that is not to be 

 forgotten in any interpretation of life; we shall re- 

 turn to it. 



But in other directions, in many branches of the 

 life tree, growth and progress can continue and 



