2 INTRODUCTION. 



that of the feveral Species, under 

 which they are ranged. 



In this Theory, which is more 

 than a fpecious Syftem, or a mere 

 agreeable Sally of Imagination, fince 

 many Traces of it appear in Nature, 

 a Drop of Water, the Diameter of 

 which exceeds not a Line, may be 

 a Sea, not only as daily Experience 

 (hews, in the Capacity which it has 

 of containing, and affording Sufte- 

 nance to Millions of Animals, but 

 alfo in the Similitude which thefe 

 very Animals may bear to feveral 

 known Species in that part of the 

 Creation, which is the Objedt of our 

 naked Eyes. 



If our Acquaintance with the Mi- 

 crofcopical W orld could be extended 

 beyond the Bounds which Nature 

 has prefcribed to it, or even was al- 

 ready carried as far as Obfervation 

 may in procefs of Time advance it, 

 the Truth of this Theory would, I 

 believe, appear in a much ftronger 

 Light, than our prefent confined Ex- 

 perience can afford, tho' abundantly 

 iinlicient to clear it from the Im- 

 putation 



i 



