INFUSORIA, OR FRESH-WATER ANIMALCULES. 29 



investigations of this nature, and by experiments con- 

 ducted with great sagacity and caution, that the eminent 

 naturalist M. Ehrenberg, discovered the interesting facts 

 relating to animalcular life, which have so astonished and 

 delighted the scientific world*. 



Our examination will begin with those animalcules 

 which are of the simplest structure the Monads ; but 

 some preliminary remarks are necessary to elucidate a 

 few general phenomena, which are observable either in 

 certain groups, or in the whole class. 



The existence of these minute beings having been 

 first detected in water containing vegetable matter, such 

 as hay, grass, &c., it was taken for granted that they 

 were peculiar to certain infusions; hence the term 



* M. Ehrenberg's splendid work is intitled "Die Infusionsthierchen 

 als Vollkomrnene Organismen. Ein Blick in das tiefere organische leben der 

 Natur. Leipzig, 1838." It is in one volume, folio, with sixty-four plates, 

 containing many hundred figures coloured from nature. It is indeed a 

 most extraordinary production, whether we consider the prodigious labour, 

 profound knowledge, and eminent talents for observation required for the 

 successful investigation of the subject, the surpassing excellence of the 

 drawings, or the marvellous nature of the beings which are therein de- 

 lineated and described. The reader who has not seen this work, though 

 he may have surveyed the beautiful and curious forms which these unpre- 

 tending pages are designed to illustrate, can have no adequate idea of the 

 fantastic shapes, and the almost endless diversity of form and structure, 

 which animal existence assumes, even in our own planet, in the regions 

 from which the microscope withdraws the veil. 



