INTRODUCTION. 



locality often contains a variety of living forms, 

 every one of which demands a profound and pa- 

 tient study, if we would know but a few things 

 concerning it. 



To man, then, is a vast and a minute. Our 

 minds ache at the contemplation of astronomical 

 immensities, and we are apt to. see the boundless 

 only in prodigious masses, countless numbers, and 

 immeasurable spaces. The Creative Mind knows 

 no such limitations; and the microscope shews us 

 that, whether the field of nature's operation be 

 what to our apprehension is great or small, there 

 is no limit to the exhibition of marvellous skill. 

 If the ''undevout astronomer" be "mad," the un- 

 devout microscopist must be still more so, for if 

 the matter be judged by human sense, the skill 

 is greater as the operation is more minute; and 

 not the sun itself, nor the central orb round which 

 he revolves, with all his attendant worlds, can 

 furnish sublimer objects of contemplation, than the 

 miraculous assemblage of forces which make up the 

 life of the smallest creature that the microscope 

 reveals. 



There is an irresistible charm in the effort to 

 trace beginnings in nature. We know that we can 

 never succeed; that each discovery, which conducts 

 back towards some elementary law or principle, 

 only indicates how much still lies behind it: but 



