THE DRAMA OF LIFE 7 



upon, the relation may be formulated as E-*>f -* o (the first 

 letters of the words Environment, function, and organism). 

 On the other hand, the Organism (to which we may now 

 give the capital letter) not only reacts, it acts. It hits 

 back ; it thrusts ; it operates upon its environment. The 

 environment being acted upon, the relation may be formu- 

 lated as 0->f->e. The real business of life is an adjustment 



0^-f^e 



of the twofold relation : = f ; and that is what we see 

 E^f-o 



continually going on in the drama of life. 



Abundance of Individuals. We have spoken of the 

 crowded stage, and the prodigality of life is certainly 

 one of its characteristics. Antarctic explorers have told 

 us that in one haul of the dredge in those icy waters 

 it was quite a usual thing to get from ten thousand 

 to thirty thousand specimens of a certain Crustacean. 

 On the surface of the small pools of water on the 

 melting ice of the mer de glace at Chamonix, M. Vallot 

 found in 1912 an extraordinary multitude of a rather 

 rare wingless insect, the ' glacier flea ', Desoria nivalis. 

 These minute and primitive forms occurred over a 

 stretch of glacier twenty metres broad by two thousand 

 metres long, and there must have been forty millions of 

 them ! 



The heather on the moor, with its firm leaves and appar- 

 ently clean twigs, does not suggest itself as a crowded home 

 of life, but that is just what it is, as Dr. Shipley found in 

 searching for grouse-parasites. He adopted the method 

 of soaking the heather in water and then centrifuging the 

 infusion, with the result that an extraordinary wealth of 

 little creatures was discovered. He gives a striking picture 

 of what would appear if we could see a square yard of 



