208 
I'HE BOOK OF FISHES 
Photograph by Curtis & Miller 
A RETORT WHICH COOKS TWO THOUSAND CANS OF SALMON AT A TIME 
Here they are given the final cooking under steam pressure. WTile large quantities of salmon are 
sold in a fresh, salted, or smoked condition, by far the major part of the catch is canned. 
duces to neglect of the needs of some 
of our most valuable creatures, is most 
emphatically and clearly refuted in sal¬ 
mon culture. 
It is a matter of general observation 
that nature is most prodigal in producing 
fish eggs and young far in excess of the 
needs of the species, and permitting the 
destruction of a very large percentage of 
the progeny before maturity is reached. 
With the advent of the human factor, 
there is a disturbance of the nice balance 
that had come to be established, and it is 
then that fish culture is demanded and 
justifies itself by saving a large propor¬ 
tion of the eggs and young that are ordi¬ 
narily sacrificed. 
MAN MORE EFFECTIVE THAN NATURE 
Just how effective ar.e the operations 
of the salmon culturist, and how strongly 
artificial propagation is now demanded 
because of the enormous drains that are 
made on the small remnants of the origi¬ 
nal progeny that have reached the re¬ 
productive age, may be seen from the 
following comparison: 
Under ordinary conditions of natural 
propagation, a certain small percentage 
of the ripe eggs are not extruded, but 
