10 



the floating cliffs of ice which tower above their surface are 

 often tinged of various hues by different kinds of Medusaria, 

 so minute that more than a hundred thousand are contained 

 in a cubic foot of water. The bottom of the vast abyss is 

 nearly paved with Zoophytes, which, in the Southern 

 Hemisphere, rise up from great depths to form extensive 

 reefs and islands. Every drop of the ocean, from the one 

 Pole to the other, teems with animalcules, and Nature has 

 amply provided for all their wants and enjoyments. 



The various classes of animals spread over the globe, 

 whether inhabitants of the dry land, or of lakes and rivers, 

 or of the atmosphere, or dispersed through the boundless 

 deep, find, in the rich and varied clothing of organic mat- 

 ter covering the nakedness of the earth, sufficient nourish- 

 ment, not only for their own subsistence and growth, and 

 for the continuance and increase of their species, but like- 

 wise sufficient to enable each individual to support various 

 tribes of parasitic inhabitants. Innumerable species of 

 Insects, Arachnida, and Annelides, move to and fro, on the 

 surface of their bodies, feeding on the excreted matters of 

 the skin, or sucking the vital fluids from the interior. 

 Various kinds of ova are deposited, matured, and hatched 

 under the skin, although the animals they contain are not 

 destined to a parasitic life. Numerous species of Worms 

 live and propagate, imbedded in the muscular and cellular 

 tissues, in the internal cavities and vessels, and in the 

 parenchymatous substance, even of the best protected or- 

 gans of the body ; as in the substance of the liver, the 

 spleen, the kidneys, and the brain itself. And various 

 fluids and secretions of the living system contain myriads 

 of Infusoria, whose singular forms, phenomena, and modes 

 of generation have been attentively examined and recorded 

 by naturalists. 



Every region of the globe presents distinct species of 

 animals: the animals of America differ from those of Eu- 

 rope; those of Europe, differ from the species of Africa 

 and Asia ; and the species of New Holland, differ from 



