ECONOMY OP NUTRITIVE MATTER. 49 



less predatory and voracious than those of the larger quad- 

 rupeds; for the spiders on the land, and the Crustacea in the 

 sea, are but representatives of the lions and tigers of the fo- 

 rest, displaying an equally ferocious and insatiable rapacity. 

 Other families, again, generally of still smaller size, are de- 

 signed for a parasitic existence, their organs being fitted only 

 for imbibing the blood or juices of other animals. 



No sooner is the signal given, on the death of any large 

 animal, than multitudes of every class hasten to the spot, 

 eager to partake of the repast which nature has prepared. 

 If the carcass be not rapidly devoured by rapacious birds, or 

 carnivorous quadrupeds, it never fails to be soon attacked by 

 swarms of insects, which speedily consume its softer tex- 

 tures, leaving only the bones.* These, again, are the fa- 

 vourite food of the Hyena, whose powerful jaws are pecu- 

 liarly formed for grinding them into powder, and whose 

 stomach can extract from them an abundant portion of nu- 

 triment. No less speedy is the work of demolition among 

 the inhabitants of the waters, where innumerable fishes, 

 Crustacea, annelida, and mollusca, are on the. watch, to de- 

 vour all dead animal matter which may come within their 

 reach. The consumption of decayed vegetables is not quite 

 so speedily accomplished; yet these, also, afford an ample 

 store of nourishment to hosts of minuter beings, less conspi- 

 cuous, perhaps, but performing a no less important part in 

 the economy of the creation. It may be observed that most 

 of the insects which feed on decomposing materials, whether 

 animal or vegetable, consume a much larger quantity than 



* So strongly was Linnzeus impressed with the immensity of the scale on 

 which these works of demohtion by insects are carried on in nature, that he 

 used to maintain that the carcass of a dead horse would not be devoured with 

 the same celerity by a lion, as it would by three flesh flies {Musca voynitoria) 

 and their immediate progeny: for it is known that one female fly will g-ive 

 birth to at least 20,000 young larvae, each of which will, in the course of a 

 day, devour so much food, and grow so rapidly, as to acquire an increase of 

 two hundred tin|ps its weight: and a few days are sufiicicnt to the produc- 

 tion of a third generation. 



Vol. II. 7 



