116 LECTURE IX. 



being often attended by the ziczac has been 

 doubted by some naturalists, but the above 

 anecdote would serve to prove the truth of it. 

 Indeed, Herodotus, an ancient historian, who is 

 generally to be depended on, states that all 

 beasts and birds avoid the crocodile except a 

 small bird which he calls the trochilus, with 

 which the crocodile is always at peace, for he 

 receives benefit from it. When the reptile gets 

 out of the water on land he opens his jaws, 

 when the trochilus enters his mouth and swallows 

 the leeches which infest it. The crocodile is 

 so well pleased with this service that it never 

 hurts the bird, A celebrated French naturalist, 

 after investigating the subject, thought that 

 there was good foundation for the story of this 

 ancient writer. 



You may ask, Of what use are crocodiles? 

 They play their part, and that an important 

 one, in the economy of nature. They are to 

 the great rivers of the tropics what wolves and 

 hyenas are to the land and the sharks to the 

 sea. In fact, scavengers clearing away offal 

 and carrion, which would poison the waters 

 and taint the air. 



But it is time to tarn to the alligator, a va- 



