THE HISTORY OF FISH-CULTURE. 491 



generally serves to create a flow of the ripe products. If the exit offers 

 any difliculty, it may be assisted by passing the finger under the belly 

 but without any effort. The simultaneous or almost simultaneous mix- 

 ture of the eggs and the milt is necessary in most cases, since with cer- 

 tain fish, as the trout, the animalcules of the milt do not live even a 

 moment, and with others, as the carp, the mucilaginous envelope of the 

 egg swells rapidly in the water and, then opposes itself to the impreg- 

 nation. For the last reason, it is important always to refrain from wash- 

 ing the eggs before fecundation, as some persons had advised doing. 



The eggs once fecundated are placed in an apparatus like those of M . 

 Oosteand M. Millet; but it appears to us preferable in all cases, when 

 j)ossible, to employ the double sieve or floating insulator of the last 

 experimenter. The fecundation is then effected in the lower part of the 

 sieve, placed in a tub full of water; and after the cover is put on, the 

 whole is transported to the river which is to be furnished : in this way 

 the spawn undergoes no change of water, from its exit from the belly of 

 the female to the period of its development. If the eggs are unencum- 

 bered, they are allowed to fall to the bottom of the sieve. If they are 

 adherent, likes those of the carp, the tench, or the barbel, care is taken 

 to introduce beforehand into the sieve some aquatic plants or twigs. The 

 little apparatus is furnished with floaters, and fastened to stakes by a 

 cord, by which it is easy to draw it to the bank, when it is to be exam- 

 ined. After the young fish are hatched, and their umbilical vesicle is 

 completely absorbed, the sieve is opened, and they are thus dispersed in 

 the very places where they are to live. With this view, shallow places are 

 chosen, which the fry generally prefer, and which are not frequented by 

 the large fish, or rather inclosures near the water-courses. The fish of 

 this early age have great agility, and commonly escape the pursuit of 

 their enemies by squatting among the pebbles, and concealing them- 

 selves in the grass or the roots of trees. They then feed naturally upon 

 lymneas, planorbis, small worms, or the spawn of frogs, but it soon be- 

 comes useful to throw them the refuse of the shambles or the kitchen, 

 and, generally, as M. Coste has advised, all animal substances which are 

 not made use of. It would seem, however, that some of these substan- 

 ces may become injurious to the fish, and M. Sivard de Beaulieu has 

 remarked that his trout always died after eating earth-salamanders. The 

 putrefaction of the substances which are not eaten offers no inconve- 

 nience in a mass of water frequently renewed like that of a brook, while 

 for this reason, and many others, the artificial nourishment of young 

 fish in narrow reservoirs is almost impracticable. They should, there- 

 fore, always be dispersed after the absorption of their vesicles, without 

 attempts to raise them painfully in small apparatus. 



These various operations are, as we see, very simple and easy, and may 

 be brought to a good result by anybody with little outlay of time and 

 expense ; but it is evident that success depends greatly upon the tact 

 and foresight of tlie operator, and that here, as in all branches of Indus- 



