iv Introduction. 



countless numbers, and immeasurable spaces. The Creative 

 Mind knows no such limitations ; and the microscope 

 shows 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 " un- 

 devout astronomer " be " mad," the undevout 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 

 heginnings 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 the geologist nevertheless loves to 

 search out the first or oldest traces of life upon our globe ; 

 and so the microscopist delights to view the simplest 

 exhibitions of structures and faculties, which reach their 

 completion in the frame and mind of man. That one great 

 plan runs through the whole universe is now an universally 

 accepted truth, and when applied to physiology and natural 

 history, it leads to most important results. 



The researches of recent philosophers have shown us 

 that nature cannot be understood by studying the parts of 

 animals with reference merely to their utility in the 

 economy of the creature to which they belong. "We do, 

 indeed, find an admirable correspondence between struc- 

 tures and the services they perform ; but every object in 

 creation, and every part of it, is in harmonious relation to 

 some grand design, and exhibits a conformity to some 

 general mode of operation, or some general disposition and 

 direction of forces, which secures the existence of the 



