150 NEW SOUTH WALES 
CHAPTER XIII. 
Acclimatization and Pisciculture. 
THis department of natural history has assumed the most important 
aspects of late years, and may be said at the same time to have become one 
of the most popular and fashionable of zoological recreations. Accord- 
ing to Dr. Giinther, artifical impregnation of fish ova was first practised 
by J. L. Jacobi, a native of Westphalia, in the years 1757 and 1763, 
who employed exactly the same method which is followed now. The 
idea of course was to favor the natural processes, and by preventing the 
waste of ova to restore the failing supplies of rivers, ponds, and streams. 
The process is as follows :—The fructifying vessel, which is tolerably large 
and with a flat bottom, is filled about one inch deep with pure water, care- 
fully kept at the same temperature as that into which the fish resorts for 
spawning. A full-roed healthy female fish having been selected, is taken 
with as much gentleness as possible by two persons, who hold it in a 
manner not likely to injure the fish, by the head and tail respectively. 
The fish is held in an upright position, and after it has ceased struggling, 
the roe, if it be quite ripe, commences to run from the vent, and in order 
to obtain as much as possible the fish’s sides and belly are gently rubbed 
downwards. If the fish be large it is never worth while to press out 
all the roe at one time. In small fishes only about half the roe is taken, 
and the fish is put back again fora day or two into the reservoir, and 
then the process is repeated. “If the eggs are quite ripe they all pour 
out into the water following cach other in rapid succession, like shot 
from a shot-belt. If the eggs do not come out quite easily, give the 
tail a gentle shake to loosen the eggs that remain in the abdomen ; but 
recollect, if you use force you will spoil the experiment. The eggs must - 
run out quite freely.”—Buckland. 
After the roe is pressed out it is spread over the bottom of the basin. 
A male fish is then taken, and a few drops of the milt is pressed out 
into the water. Pressure is made on the abdomen of the male in the 
same way as the female. If the milt is ripe, it will instantly discolour 
the water and make it white. The roe and milt are then stirred up 
with the finger, and left for about five minutes. The milk-coloured 
water is then poured off, and fresh water gently added until the eggs 
appear quite clear again. The milt of one male will fertilize the ova of 
many females, and the fish can be returned to the sea or river none the 
worse for the operation. Then the impregnated ova are either placed 
into the breeding boxes or packed for exportation, The manner 
of packing is this :—The boxes are about 6 inches in height and width, 
and 2 feet long. On the bottom is a layer of damp moss, mixed with 
ice (if the temperature of the season or the country require it). On this is 
spread a damp linen cloth, over it a thin layer of ova is laid. Another 
wet linen cloth and more moss completes the packing, which has to be 
rather tightly fastened to prevent shaking and friction. In many places 
in Europe no roe is packed until two black spots appear in the ova (the 
eyes), because the fish bear transport better in that state. If a long 
transit be anticipated, the ice arrangements must be different, because 
melted ice water injures the roe. 
