A Frozkx WoHLi) 207 



new water-wdrld. Perliaps, aj^aiii, a heron drops 

 a halt-eaten lish into tlie water- — a fish which is 

 dead itself, hut has adhering to its scales or skills a 

 few small fresh-water crustaceans and nioUusks. 

 Perhaps a flood brinj^s a minnow or two and a 

 weed or two from a nei!4hb()urin<4 stream; perhaps 

 a wanderin<4 froj^ trails a seed on his feet from 

 one pool to another. liy a series of such acci- 

 dents, each trivial in itself, an isolated pond 

 acquires its inhabitants ; and you will therefore 

 often lind two ponds close beside one another 

 (but not connected bv a stream), the plants :md 

 animals of which are nevertheless quite different. 



Now, the pond in sunnner is one thinj^ ; the 

 pond in winter is quite another. For just reflect 

 what winter means to this little, isolated, self-con- 

 tained community I The surface freezes over, and 

 life in the mimic lake is all but suspended. Not 

 an animal in it can rise to the top to breathe ; not 

 a particle of fresh oxygen can penetrate to the 

 bottom. Under such circumstances, when you 

 come to think of it, you mi^ht almost suppose 

 life in the pond must cease altogether. But nature 

 knows better. With her infinite cleverness, her 

 infinite variety of resource, of adaptation to cir- 

 cumstances, she has invented a series of extra- 

 ordinary devices for allowing all the plants and 

 animals of a pond to retire in late autunni to its 

 unfrozen depths, and there live a dormant exist- 

 ence till sunnner comes attain. Taking tiiem in 

 the mass, we may say that the population sink 

 down to the b()ttv)m in November or December, 



