THE ANIMAL KINGDOM. 299 



An irresistible desire to change their locality or country 

 is usually seen only in animals in the full flush of strength. 

 Nevertheless, it is also observed in certain young creatures 

 just hatched. This takes place in spring among the eels. 

 The progeny of this fish, the life-history of which is not yet 

 fully unravelled, pass up our rivers at this time in such com- 

 pact swarms that all the travellers seem to touch each 

 other ; anything like numbering them would be impossible. 



Near the steep banks of the Seine these young eels form 

 a band quite a yard wide, which sometimes takes more than 

 a week to pass the neighborhood of Rouen, and after that 

 time these millions of animals suddenly disappear without 

 leaving any trace. Whence does this animated milky way 

 reach us, and what becomes of this diaphanous and scarcely 

 developed brood ? This is as yet an impenetrable secret. 1 



Our commercial relations with distant countries also favor 

 the migrations of certain animals, but still not to such an 

 extent as one might be tempted to think. Transported to 

 a strange climate, they mostly die : the cold freezes some, 

 the heat suffocates others. It is not uncommon to see in 

 European ports some serpent or spider from tropical coun- 

 tries, which our ships have disembarked along with their 

 cargoes of dyewoods. But stupefied by the want of sunshine 

 these exiles soon die, regretting their happier country. 



1 According to M. Coste, a single pound of the fry contains about 1800 little 

 eels. This progeny, looking like thread-worms, inspires some persons with disgust. 

 In some countries they are fished for by torchlight and used for food. In Caen, 

 where this takes place, the fry is sold in the markets and streets in large buckets. 

 Its price varies according to the yield of the fishery ; generally it is sold at about 

 a franc a quart. It is eaten in different ways, prepared with white sauce, fried, 

 and even made into pates. 



