708 The Outline of Science 



are individuals. "Though the closure is never complete, the inde- 

 pendence never absolute, the harmony never perfect, yet systems 

 and tendency alike have real existence." The individual is unity 

 in diversity in what it is and what it does a whole whose 

 diverse parts all work together, ensuring continuance. When it 

 transcends the limits of its substance, Mr. Huxley says, that is 

 personality. 



But in addition to the abundance of life alike of individu- 

 alities and of individuals there is the quality of insurgence. Liv- 

 ing creatures press up against all barriers ; they fill every possible 

 niche all the world over ; they show that Nature abhors a vacuum. 

 We find animals among the snow on Monte Rosa at a height of 

 over 10,000 feet; we dredge them from the floor of the sea, from 

 those great "deeps" of over six miles where Mount Everest would 

 be much more than engulfed. It is hard to say what difficulties 

 living creatures may not conquer or circumvent. You may find 

 insects in hot springs in which you cannot keep your hand im- 

 mersed, or Rotifers and other small fry under fifteen feet of ice 

 in the little lakes of Antarctica; you find a Brine-Shrimp and 

 two or three other animals in the Great Salt Lake; you find a 

 fish climbing a tree, and thoroughly terrestrial types like spiders 

 having species living under water; there is, as Sir Arthur Shipley 

 has shown, a bustle of life on the dry twigs of the heather. When 

 we consider the filling of every niche, the finding of homes in 

 extraordinary places, the mastery of difficult conditions, the 

 plasticity that adjusts to out-of-the-way exigences, the circumven- 

 tion of space (as in migration), and the conquest of time (as in 

 hibernation), we begin to get an impression of the insurgence 

 of life. We see life persistent and intrusive spreading every- 

 where, insinuating itself, adapting itself, resisting everything, 

 defying everything, surviving everything! 



The great Sequoia trees (see illustration, facing p. 604) 

 may be taken as emblems of life's tenacity, for they have been 

 known to flourish for over two thousand years. One of the oldest 



