THE NEW AKT OF BIVEBDING FISH. 33 



head and held over it, if the eggs have come to ma- 

 turity they will fall into it ; if not, by pressing the 

 belly lightly with the palm of the hand they can be 

 made to do so. The male fish is then treated in the 

 same manner. When from the male enough milt has 

 been pressed out to whiten the surface of the water, 

 the operation of fecundating the eggs is complete." * 



But in order to complete his experiments and turn 

 them to account in industrial application, he had 

 prepared beforehand, to receive the fecundated eggs, 

 long hatching-boxes, in the arrangements of which 

 were combined all the conditions with which he had 

 observed the females surrounded their spawn when 

 deposited at the bottom of streams. He thus de- 

 scribes this hatching apparatus : 



" The box may be constructed of any suitable 

 size : for example, eleven feet long, a foot and a half 

 wide, and six inches high. 



" At one extremity should' be left an opening six 

 inches square, covered by a grating of iron or brass 

 wire, the wires not being more than four lines apart. 

 At the other extremity on the side of the box should 

 be made a similar opening, six inches wide by four 

 inches high, similarly grated ; this one will serve for 

 the escape of the water, the other for its entrance, 

 and the grating will prevent water-rats or any de- 

 structive insects from reaching the eggs. The top of 

 the box should be closely shut for the same reason, 



* Duhamel, op. cit., 2d part, p. 334 

 2* 



