30 HISTORY OP THE FOUNDATION 0¥ THE 



assume that only fifty full cod are used for artificial incu- 

 bation^ then the young produced would be 450 millions. 

 Now, the whole catch of cod by human agencies on the 

 coasts of North America is only 150 millions, so that fifty 

 cod, so treated, would more than suffice to produce that 

 number. Man, however, is an insignificant factor in the 

 destruction of fish, for they have many enemies even of 

 their own kind to encounter. The blue fish, which abounds 

 on the American coasts, is a cruel tiger of the sea. It does 

 not swallow other fish for food, but it snaps a mouthful out 

 of one fish and then attacks another in a like way, eating, it 

 is believed, its own weight of fish for food daily. This, and 

 the other enemies to the young cod, interfered greatly with 

 the labours of the artificial incubation ; but persistence has 

 been rewarded with success. The cod thus artificially 

 hatched are attached to the place of their birth, and do not 

 seem to know their way to the coasts of Newfoundland ; 

 and so they keep to the shores of the States, and are now 

 freely caught in summer, being called by the fishermen 

 " Commission cod." If I do not tire you, let me give one 

 other instance. The American shad is a fish greatly 

 esteemed by our Transatlantic kin. It only spawns on the 

 sea coasts at a temperature within a few degrees of 60° F. 

 If cold rains lower the temperature to 55°, or if hot weather 

 raises it to 65°, the shad run out to sea to spawn. Formerly, 

 after a cold or hot spell of this kind, the fishermen knew 

 that in the fourth year after it there would be a famine of 

 shad, but this occurs no longer ; for the Commission vessels 

 now follow the shad to sea, secure their eggs, and hatch 

 them artificially. So no famine is now known. Although 

 I would have preferred to support the motion for marine 

 laboratories more on the ground of their importance to 

 abstract science than to show those who look to practical 

 applications the enormous benefits which come from a study 

 of the habits of marine life, yet had I time, I could refer 

 to the important applications made recently in the United 

 States on the subject of oyster cultivation, and to the 

 valuable and interesting paper of Professor Cossar Ewart 

 on the spawning of herring in Scotland — a subject familiar 



