CHAPTER X 



NATURAL ENEMIES OF THE AMERICAN 



OYSTER 



HAT may be called the balance of nature 

 the interdependence of organisms on each 

 other as it appears in a multitude of forms, 

 is one of the most striking and interesting of 

 the phenomena that the naturalist observes. These vital 

 relations among living things are frequently complex, in- 

 volving many different species of both animals and plants. 

 They are not fixed, but even without man's influence, 

 are subject to many changes. 



One of the conclusions derived from the study of the 

 interrelations of organisms is that every animal and 

 every plant has enemies that may injure or destroy it. 

 These enemies are not of a single species, but many. 

 Wild rabbits, for example, in order to exist must escape 

 from foxes, wild members of the cat family, minks, 

 weasles, hawks, snakes, and many other vertebrates; and 

 in addition to these they must contend against a host of 

 insect and worm parasites. The list does not end here, 

 but includes many deadly bacterial and perhaps proto- 

 zoan parasites. While this may seem to be an extreme 

 case, one may be perfectly certain that even the eagle and 

 the lion, that we are accustomed to think of as fearing no 

 foe, are subject to attack by many deadly enemies. 

 Animals and plants in nature have, through the action 



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