118 DISCOVERY OH. 



develops in stagnant pools and somewhat resembles a 

 horsehair in appearance, and as a dry horsehair when 

 placed in water may twist about somewhat in the fashion 

 of this parasite, one was supposed to be produced from 

 the other, after which the transition from the thread- 

 worm to the eel became easy to a credulous mind. This 

 simple way of explaining the origin and development of 

 the common eel satisfied the uncritical observer, but 

 the truth was much more difficult to discover. 



From the days of Aristotle onward the actual mode 

 of development of the eel was a mystery. It was 

 known that large eels pass from rivers into the sea at 

 certain seasons, and that diminutive young eels, called 

 in this country elvers, ascend the rivers in enormous 

 numbers. But until Profs. Grassi and Calandruccio, 

 of Rome, investigated the matter in 1895, no one in 

 any country had been able to discover how the elvers 

 were produced. These naturalists proved that the eels 

 which annually descend the rivers travel very long 

 distances, until they reach the ocean. It is not known 

 exactly in what part of the ocean spawning takes place, 

 but the eggs develop into strange, colourless, trans- 

 parent, thin-bodied creatures, which were thought to 

 be a special family of fishes, but are now known to be 

 really the larvae of eels. After attaining a certain size 

 the larva ceases to feed, its body shrinks, and it assumes 

 the very different form of the elver which ascends our 

 rivers. A more wonderful series of changes than that 

 thus revealed would be difficult to find. The whole 

 story of the eel and its spawning reads almost like a 

 romance instead of scientific reality. 



Another curious case of deceptive appearance gave 

 rise to the widespread belief in the production of honey 

 by bees in the carcasses of dead animals, and principally 



