4 FEEDING AND DIGESTIVE POWER OF FISH. [CHAP. i. 



sprats and sardines, bait the ground with prepared cod-roe, 

 which, by the way, adds very largely to the expense of that 

 branch of fishing in the Bay of Biscay. I may also remind my 

 readers, as an evidence of fish having a strong sense of smell, 

 that salmon-roe used to be a deadly trout-bait, but fishing 

 with salmon-roe is now illegal. It has been said by some 

 naturalists that fish do not hear well, but that assertion is 

 contrary to my own experience ; for on making repeated trials 

 as to the sense of hearing in fish, I found them as quick in 

 that faculty as they are sharp in seeing ; and have we not all 

 read of pet fish being summoned by means of a bell, and 

 of trouts that have been whistled to their food like dogs? 

 Water is an excellent conductor of sound : it conveys a noise of 

 any kind to a greater distance, and at nearly as great a speed 

 as air. Benjamin Franklin used to experiment on water as a 

 conductor, and soon arrived at the conclusion that its powers 

 in this way were wonderful. By striking two stones together, 

 the experimenter will find that the sound is conveyed to a great 

 distance, and also that it is very loud. Most kinds of fish are 

 voracious feeders, and prey upon each other without the 

 slightest ceremony ; and the greatest difficulties of the angler 

 are experienced after the fish have had a good feed, when 

 even the most practised artist, with his most seductive bait, 

 will not induce them to nibble, far less to bite. Many of our 

 fish have a digestion so rapid as only to be comparable to 

 the action of fire, and in good feeding-grounds the growth of 

 a fish usually corresponds to its poAver of eating. In the sea 

 there exists an admirable field for observing the cannibal pro- 

 pensities of the fish world, where shoals of one species have 

 apparently no other object in life than to chase another kind 

 with a view to eat them ; and what goes on in the sea on a 

 wholesale scale is imitated on a smaller scale in the loch and 

 the river. To compensate for the waste of life incidental to 

 their place of birth and their ratio of growth, nature has en- 



