[3] ARTIFICIAL PROPAGATION OF FISH. 493 
§ 2.—Artificial fecundation of free eggs. 
For this purpose one may use any vessel of glazed clay, porcelain, 
stone, wood, W&c.; the circumference of the upper edge should almost be 
equal to that of the bottom, which ought to be flat, so the eggs can 
spread over a certain surface and not be crowded. Water is poured into 
this vessel so as to cover the bottom to the depth of about 10 centimeters. 
This water, which should be clear, may be taken either from the stream 
or pond where the hatching apparatus is to be placed, and where the eggs 
ought to develop, or from those waters where the fish about to be propa- 
gated generally live. It is necessary to ascertain if the water has the 
temperature observed at the time of the natural spawning. When the 
water of those rivers is used in which a fish about to be manipulated pro- 
pagates naturally, its primitive temperature should above everything 
else be preserved. For this purpose, and if one operates in the open air, 
as near a trout-brook, it will be preferable, in order to accelerate the 
manipulations, to operate only on small quantities and to use fresh water 
every time. 
As soon as these preliminaries are finished, one takes up a female 
fish with the left hand and holds it perpendicularly by the fins of the 
head over and as close as possible to the vessel. When the fish is in 
this position the eggs which are 
near the anal orifice are emitted 
through their own weight. If this 
is not the case, the belly of the fish 
ought to be pressed very gently by 
moving the thumb and forefinger 
up and down. (Fig. 3.) 
As soon as the eggs, which have 
been extracted in the above man- 
ner, form a thin layer at the bot- 
tom of the vessel, one takes a male 
fish, treating him in exactly the 
same manner as the female, until 
= the water becomes slightly turbid, 
r assumes the appearance of milk 
which has been violently stirred. 
This mixture is thereupon stirred 
rita either with the tail of the male fish, 
held in the water during the operation, or with the hand, or with the 
beard of a brush ora feather. After letting it stand for 5 or 10 min- 
utes fecundation is accomplished. 
If the strength of the tail of the fish operated upon necessitates the 
employment of an assistant, the above manipulations are modified; the 
assistant holding the tail of the fish whose convulsive and irregular 
motions inconvenience the operator. The fish is then, necessarily, in 
