186 Observations on the DeveIoj)ment [''T^L\!v7Lr&^^ 
be taken alive, at a time when they are just ready to deposit their 
eggs, or to spawn, as it is called. This time will be known to most 
fresh- water fishermen, whether professional or amateurs. Some one 
endued with the requisite knowledge of the fish and its habits should 
be furnished with instructions to look out for pike, male and female, 
in the state alluded to, and when found, they must be caught in the 
net, and kept alive in water until they reach the experimenter's or 
observer's hand. 
I obtained my supply of eggs from a friend who was studying 
the subject of egg development. The pike were netted early in the 
month of April, the keeper of the (preserved) ponds having been on 
the watch for a few weeks before. The fish were brought to town 
and transferred from the fish-can to a tub of cold water. There 
were two or three specimens of each sex. On the 14th April, 1866, 
at 10 A.M., a well-grown female fish was taken out of the tub and 
a wet towel wrapped around her head, with a double purpose — in 
the first place to maintain a humid atmosphere in the neighbour- 
hood of the gills, so as to keep the respiration process going ; in 
the second place, to prevent any attempt at biting the operator, 
the pike having powerful jaws and sharp teeth, and being by no 
means disinclined to resent interference with its liberty. The fish 
was then laid on a broad, shallow dish, containing a little water, and 
the four fingers of a hand passed along the sides of the animal with 
a gentle stroldng pressure. By this means, if the fish is ripe, or 
ready to spawn, the eggs will be found to pass out quite easily, 
without any force, so to speak, being made use of, and as it is pos- 
sible to nearly empty the ovary, a great number of eggs is obtained. 
When a sufficient number was collected, the fish was returned into 
the water, and a male pike was taken. This was treated in the 
same way. A very small quantity of the male spawn is sufficient 
to fertilize the whole number of eggs obtained from a female fish. 
There is sometimes a difl&culty at this stage of the proceedings to 
get the milt to yield its contents : in such a case the fish may be 
cut open, and a small piece of the milt placed in the dish containing 
the eggs, and agitated amongst them for about five minutes. The 
fragment should then be carefully removed, as otherwise it will de- 
compose, and cause the death of the now fertilized ova. 
All that is necessary to do further is to put the eggs into a 
suitable receptacle (on the bottom of which they should lie at not 
more than two in depth), to pour in a good quantity of fresh, clean, 
hard water (from a tap will do), and to cover the vessel with a pane 
of glass ; this keeps out dirt and dust falling upon the eggs — which 
adhering to them will interfere with microscopic observation — and 
yet allows of the free passage of light. The water will require 
changing three or four times a day ; this must be done gently, 
either by decantation or by a syphon. Fresh water must be added 
