ARTIFICIAL BREEDING OF SALMON. 205 
with water from the latter till they are both equal. 
Great care must be taken not to hurry this operation. 
The contents of the box should then be emptied 
into a good-sized tub half filled with water of the same 
temperature as that in the hatching-case. By gently 
moving the hand about among the moss, the ova will 
sink to the bottom, and the moss remain floating on the 
surface. The water should now be drained off, and the 
ova at once deposited in the hatching-boxes. 
Should the water in the hatching-boxes, however, be 
of a higher temperature than the moss in which 
the ova were conveyed, these can be at once removed 
into the hatching-cases after they have been detached 
from the moss as above described. 
On THE ENEMIES TO THE OVA AND YounG FIs. 
The greatest care must be taken to prevent the en- 
trance of insects and larve into the hatching apparatus. 
The most dangerous enemy to the ova and the young 
fish is, perhaps, the water-newt (Sorex fodiens). If the 
apparatus cannot be raised to a sufficient height above 
the ground, it should be protected with a perforated tin 
or zine lid. 
A curious instanee occurred at the hatching esta- 
blishment at Greffsen, a water-cure ‘establishment 
near Christiania, a few years ago. The apparatus was 
