156 AMERICAN FISH CULTURE. 



transparent as the water itself; but if they turn milky, 

 and look like half-boiled sago, they are spoiled. 



" The contents are not, however, to be thrown away, 

 without taking up some in the hand, when it will likely 

 appear that but a small part are addled, while the rest re- 

 main transparent. With further progress the embryo may, 

 with a weak glass, be easily seen moving in the egg, which 

 then is not so clear, and at the end of sixty hours (with, 

 sunshine and water at 75°), the box will be found alive 

 with tiny fry, almost transparent, except the eyes, swim- 

 ming freely, with their heads up stream. In confinement 

 they cannot be kept, because the yolk-sac does not suffice 

 for their support for more than one or two days. But care 

 must be taken to liberate them in a safe place. Green 

 observed that, on setting them free among the shallows 

 near shore, the dace {Argyreus) and other little fishes 

 rushed to the .spot, and commenced jumping at them. In 

 the stomach of a dace, he found fourteen shad fry. Then, 

 by a series of most ingenious experiments, he discovered 

 that the fry, so far from frequenting the shallows, like 

 many minnows, made directly for the main current, in mid- 

 river. How different this from the young trouts that lie 

 aJmost helpless for forty-five days, and then are fain to hide 

 behind stones and roots ! Whereas, these minute, trans- 

 parent, gelatinous things push boldly for the deep, swift 

 current, where they are too insignificant to be attacked by 

 the great fishes. Will the physicists tell us what ' corre- 

 lation and conservation of force' produces this, or will the 

 Darwinians set forth how, some millions of years gone, a 

 particular shad fry, finding by accident that he did not get 



