[21] ARTIFICIAL PROPAGATION OF FISH. oll 
Those fish which live on their congeners may be fed with the spawn 
and young fish which they have produced. If it is not possible to do 
this, the following articles may be used to advantage: whiting, reduced to 
a paste; frog meat, cut, dried, and made into a very fine powder; veal or 
beef cooked and chopped up fine, or blood dried and pulverized. If 
this kind of food is used, the basins should be well cleaned from time to 
time, so as to prevent any accumulation of decaying animal matter. 
As soon as the fish are large and strong enough to encourage the hope 
that they will not fall a prey to their worst enemies, they are let loose 
in the water which is to be stocked with them, or they are forwarded to 
those places where that particular kind of fish is desired, in kegs filled 
with water. 
We are not in favor of any prolonged stay in the piscicultural estab- 
lishments, except where foreign breeds of fish are to be acclimatized, 
where rare species are to be multiplied, or where continued stocking of 
waters necessitates the constant production of young fish; and even in 
this case it will be necessary to consider whether it is not preferable to 
place the young fish in basins specially set aside for that purpose. 
§ 2. Sickness of young fish. 
When fish-ponds are established in much frequented localities, it often 
happens that dead fish are found at the bottom. They generally sink 
to the bottom with their mouths wide open, and when examined the en- 
tire buccal cavity is found to be filled with blackish flakes. These are 
produced by small atoms floating in the air, which fall into: the water 
and gather into small flakes, which the movements of the fish scatter 
throughout the whole pond. This detritus, which is too light to be swal- 
lowed, enters the respiratory organs, obstructs them, and finally causes 
asphyxia. 
This evil may be remedied by supplying the apparatus with a double 
bottom, either by means of a wicker frame, or some tissue with large 
meshes, which is placed between the bottom of the basin and the space 
reserved for the fish. 
§ 3. Acclimatization. 
The possibility of acclimatizing fish was demonstrated a long time 
ago. Among the ancients, the Chinese* and the Romans hatched the 
* Several authors tell us that the Chinese have from time immemorial pursued a 
method which only now begins to be known in Europe. Inquiries relative to this 
subject show that their whole merit consists in having transplanted eggs from one 
water to the other. For this purpose they gather spawn which has been fecundated 
in a natural manner on mats, which answer the same purpose as our artificial spawn- 
ing-boxes, and which aresold by measure. No one willseriously consider the method 
recommended by their authors, to put spawn in egg shells, to seal these up hermet- 
ically, and have them hatched by a bird!! 
