74 MARVELS OF FISH LIFE 
red. As already described, it has no shell in the ordinary 
sense of the term, but is covered with a strong, partly 
elastic membrane, and if thrown upon a hard surface 
it will bounce like a rubber ball. Salmon eggs possess 
characteristics which, though they require certain con- 
ditions in their transfer, make it possible for them to 
be sent all over the world. 
For twenty-four hours after the egg has been taken 
from the fish, handling or a slight shock or jar does not 
injure it, and it can be sent by rail either in or out of 
water. After twenty-four hours, when the first stage of 
visible development has begun, the egg becomes exceed- 
ingly delicate, and the slightest jar will now kill it. 
This susceptibility to a jar or shock continues until 
about one-third of the incubation has been passed 
through, and the extraordinary thing is that the eggs 
which would certainly be killed by handling on one 
day can be handled on the very next with impunity. 
The expert fish culturist can tell when an egg can be 
handled without the fear of injuring it by watching the 
development of the tail of the future fish as seen 
through the egg membrane. 
After this immunity to shock has been arrived at, 
the egg can be packed for transport. 
The time of hatching varies in common with all 
other fishes’ eggs, according to the temperature of the 
water. The colder the water, the longer is the hatching 
delayed. It is by taking advantage of this fact that 
long distance transport is possible. Eggs, which at the 
