DARWINISM AND OTHER BRANCHES OF SCIENCE. 357 



a similar taste is widely spread among the fowls of the 

 air and the fishes of the sea. The herring has no defence 

 from innumerable enemies but its agility and its caution. 

 Around the shoal swarm troops of porpoises, while pollack 

 and various other predatory fish devour the herrings in 

 myriads. The female herring lays a stupendous quantity 

 of eggs. It is perfectly certain that only a very minute 

 fraction of these eggs ever reach maturity. If only one 

 per cent, of the eggs grew to full size and reproduced 

 more herrings, the herring population of the sea would 

 multiply enormously every year. This cannot always, or 

 indeed often, be the case, and we are thus compelled to 

 believe that out of every million herring eggs only a 

 small fraction usually come to maturity. To those who 

 have ever observed the herring this appalling mortality 

 will not seem strange. 



To begin with, when the eggs are laid the flat fishes 

 congregate and feast thereon to such an extent that fisher- 

 men repair to these spots and catch the flat fish in scores 

 with their stomachs filled with the eggs of the herring. 

 No doubt there are many other enemies at this stage, 

 so that vast multitudes of the herring eggs never become 

 hatched at all ; even those that are hatched have indeed 

 a bad time of it. Around our coasts we see in the 

 autumn shoals of the tiny herrings pursued and devoured 

 by hosts of young codfish and mackerel. Sometimes the 

 fish surround the shoal completely, and the miserable 

 prey cluster together near the top of the water in a vain 

 hope of safety ; but, alas ! here the enemies from the air 

 attack them. Sea-gulls crowd to the spot and swallow 

 the young herrings in mouthfuls, and once a shoal has 



