APPENDIX. 247 



same reason ; but a grated opening, similar to the rest, six 

 inches square, may be left to give light to the young fish. 

 This, however, is not absolutely necessary. 



" A suitable place should then be chosen for the box 

 near a rivulet, or what is still better, near a pond supplied 

 with running water, from which may be drawn, by a little 

 canal, a stream, say an inch thick, which should be made 

 to pass continually through the gratings and through the 

 box. 



" Lastly, the bottom of the box, to the thickness of an 

 inch, should be covered with sand or gravel, and over this 

 should be spread a bed of stones of the size of nuts or 

 acorns ; thus will be made a little artificial brook running 

 over a gravelly bottom." 



The fecundated eggs are spread " in one of the boxes so 

 placed, and the water of the little rivulet passes over them, 

 care being taken that it does not run with such rapidity as 

 to displace and carry away with it the eggs, for it is neces- 

 sary they should remain undisturbed between the pebbles." 



" Care must be taken to remove, from time to time, the 

 dirt which is carried by the water and deposited on these 

 eggs ; this can be done by stirring about the water with a 

 quill feather." 



Using such precautions, and profiting by the experience 

 gained in the course of his experiments, Jacobi perfectly 

 succeeded in his attempts, and to him belongs, unquestion- 

 ably, the merit of first artificially fecundating the eggs of 

 fishes, or at least, the first publication of the principles 

 of the art and of the results which would logically flow 

 from it. 



