THE PERCH 



55 



in most spendthrift fashion, creating living organisms whereof 

 not one in a hundred, it may be not one in a thousand, have 

 the most infinitesimal prospect of attaining maturity. At 

 other times she treats the vital principle as a rare treasure, 

 hedging the embryo with elaborate defence, and providing 

 infinite protection for the young creature. The same want 

 of principle, as we may call it in a Pickwickian sense, is 

 apparent in all living things, animal and vegetable. The end 

 is everything ; the means indifferent. Thus the oak produces 

 comparatively few acorns, each enclosed in a horny sheath to 

 protect it from injury ; while the fig-tree contains in each 

 single fruit more living seeds than are borne by a large oak. 

 Mammals which undergo long and laborious gestation are 

 endowed either with high intelligence to provide for their 

 offspring, as is the case with man, or with formidable strength, 

 like the elephant. In no class of animals are these extremes 

 more manifest than in fish. The sharks and rays, fish of a 

 very primitive type which existed many ages before the modern 

 bony fishes which we are considering had been evolved, lay 

 few and large eggs. Some species may possibly be vivi- 

 parous, that is, their young are produced alive, thereby 

 escaping all the perils incident to eggs and tender alevins 

 abandoned to chance ; but most of the sharks produce a few 

 — very few — eggs, each of which is enclosed in a large purse 

 or sheath of an exceedingly tough, horny substance. When 

 the young creature is ready for a start in life, this case 

 splits along one of its ends, and a little shark, dog-fish, or 

 ray, already several inches long, swims abroad upon a career 

 of destruction. 



The cod, on the other hand, affords an instance of the 

 opposite extreme. A single large female may deposit as many 

 as nine million eggs, every one of which is the germ of 

 a potential twenty-pounder. Yet neither sharks nor cod 

 increase perceptibly in numbers. By severe economy of the 

 principle of life in one case, by reckless disdain for it on the 



