PHASES OF ANIMAL LIFE 



to the spring fields. Then came two or three very se- 

 vere winters and the cheery call of the quail is heard 

 in our fields no more. The same severe winters cut 

 off the race of 'possums, which had multiplied in our 

 country till they were as common as rabbits. A few 

 years ago there was a fearful ebb in the life of the 

 ruffed grouse, all over the country from Maine to 

 Minnesota. More than fifty per cent of the birds 

 vanished in a single season. The cause of it has not 

 yet been cleared up. Now the birds are slowly re- 

 appearing. 



The natural balance of life in any field cannot 

 long be disturbed. Though Nature at times seems 

 to permit excesses, yet she sooner or later corrects 

 them and restores the balance. The life of the 

 globe could never have attained its present develop- 

 ment on any other plane. A certain peace and har- 

 mony have come out of the perpetual struggle and 

 warfare of opposing tendencies and forces. 



The waters of the globe all tend to seek the same 

 level, but this equilibrium is constantly broken by 

 the solar forces, so that the currents flow perpetu- 

 ally. When one force pulls down, another force 

 builds up. 



The weasel is the most fierce and bloodthirsty of 

 all our smaller mammals; mice and rats, squirrels 

 and rabbits, and birds vanish before him, yet he 

 does not overrun our fields and woods; he is quite 

 a rare beast; some unknown enemy or condition 

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