152 ANIMAL INDIVIDUALITY [OH. 



of individuality, we have been able to see it made 

 objective in the various streams and masses of proto- 

 plasm which we call animals and plants, and to trace 

 an upward progress in its course, at the same time 

 getting light on many related problems of biology. We 

 have seen the totality of living things as a continuous 

 slowly-advancing sheet of protoplasm, out of which 

 nature has been ceaselessly trying to carve systems 

 complete and harmonious in themselves, isolable from 

 all other things, and independent. But she has never 

 been completely successful: the systems are never 

 quite cut off, for each must take its origin in one 

 or more pieces of a previous system ; they are never 

 completely harmonious, as MetschnikofFs long list 

 of the " disharmonies " in man will show ; and they 

 are never completely independent. These very 

 incompletenesses, due to the limitations of the 

 material stuff with which life has to work, have 

 proved the foundations of fresh advance. It is just 

 because every system is bound to be in some degree 

 dependent, that a number of systems can adjust their 

 various Avays of dependence to each other, till a 

 condition of minimum waste and maximum inter- 

 dependence is gradually set up, and a new system, 

 better equipped than any and all of the earlier ones, 

 is made. 



These systems are individuals, and it thus comes 

 about that individuals exist in grade upon grade, 



