INTRODUCTION. 13 



formed by the temporary influence of the sun upon the sur- 

 face of the arctic snows, animalcules have been found in 

 a state of activity ; and the ocean of those inhospitable regions 

 is tenanted, not only by the whales and other monsters which 

 we think of as their chief inhabitants, whose massive forms 

 are only to be encountered " few and far between," but by 

 the shoals of smaller fishes and inferior animals of various 

 kinds upon which they feed, and through vast fleets of which 

 the mariner sails for many miles together. 



On the other hand, even the hottest and most arid portions 

 of the sandy deserts of Africa and Asia are inhabited by 

 animals of various kinds, provided that vegetables can find 

 sustenance there. The humble and toilsome ants make these 

 their food, and become in turn the prey of the cunning ant- 

 lion and of the agile lizard j and these tyrants are in their 

 turn kept under by the voracity of the birds which are 

 adapted to prey upon them. The waters of the tropical ocean 

 never acquire any high temperature, owing to the constant 

 interchange which is taking place between them and those of 

 colder regions ; but in the hot springs of various parts of the 

 world, we have examples of the compatibility of even the 

 heat of almost boiling water with the preservation of animal 

 life. Thus in a hot spring at Manilla which raises the ther- 

 mometer to 187, and in another in Barbary whose usual tem- 

 perature is 172, fishes have been seen to flourish. Fishes 

 have been thrown up in very hot water from the crater of a 

 volcano, which, from their lively condition, was apparently 

 their natural residence. Small caterpillars have been found 

 in hot springs of the temperature of 205; and small black 

 beetles, which died when placed in cold water, in the hot 

 sulphur baths of Albano. Intestinal worms within the body 

 of a carp have been seen alive after the boiling of the fish for 

 eating ; and the inhabitants of some little snail- shells, which 

 seemed to have been dried up within them, have been caused 

 to revive by placing the shells in hot water for the purpose of 

 cleaning them. 



The lofty heights of the atmosphere, and the dark and 

 rayless depths of the ocean, are tenanted by animals of 

 beautiful organisation and wonderful powers. Vast flights of 

 butterflies, the emblems of summer and sunshine, may some- 

 times be seen above the highest peaks of the Alps, almost 



