INFUSOEIA. 31 



CHAPTER III. 



INFUSOEIA*. 



(63.) IF we examine a drop of water taken from any pond or ditch 

 in which vegetable or animal substances have been permitted to undergo 

 incipient decay, with a microscope even of very limited power, we must 

 soon perceive that it swarms with innumerable organisms, which are 

 evidently endowed with life and exhibit considerable activity. Prom the 

 circumstance of their extreme minuteness, these microscopic beings were 

 designated by their first discoverers " Animalcules" to which appella- 

 tion, from the fact of their generally making their appearance in vege- 

 table infusions, the term " Infusorial " was very generally superadded 

 by their earlier investigators. Progressive improvements in the struc- 

 ture of the microscope, however, soon made it apparent that the so- 

 called Infusorial or Microscopic Animalcules embraced a vast variety 

 of different forms of living beings possessed of little in common except 

 their invisibility to ordinary observation : the larvae and even the adult 

 states of innumerable Insects, Crustaceans, Worms, and Zoophytes were 

 all comprehended under a term so general ; and even microscopic Algae, 

 Desmidieae, and Diatomaceae, now universally acknowledged to be mem- 

 bers of the vegetable domain of Nature, were included in this chaotic 

 assemblage organisms widely dissimilar from each other both in their 

 shape and structure. 



It would be foreign to our present purpose to analyse the succes- 

 sive steps whereby something like order has at length been established 

 in a scene of such apparently inextricable confusion, and how pari 

 passu with the improvement of the microscope has been the rapid 

 advancement of knowledge in connexion with these until so late a 

 period unknown existences ; suffice it to say that, in accordance with 



* Vide Miiller, 1786 : Ehrenberg, Infusionsthierchen, 1837 : Dujardin, Hist. Nat. 

 des Zoophytes : Pineau, Ann. Sc. Nat. 3 e se>. tomes iii. v. ix. : Stein, Wiegm. Archiv, 

 1849; id. Sieb. and Zol. Z. iii.; id. Die Infusionsthierchen, Leipzig, 1854: Peltier, 

 PInstitut, 1836 : Focke, Isis, 1836, and Physiolog. Studien : Kutorga, Naturgesch. 

 d. Infusionsthierchen : Meyen, Muller's Archiv, 1839 : Pritchard, Infus. Anim. : 

 E. Jones, Ann.Nat. Hist. 1839 : Werneck, Ber. d. Berl. Akad.1841 : Erdl, Mull. Archiv, 

 1841 : Griffith, Ann. Nat. Hist. 1843, xii. : Siebold, Lehrbuch Vergl. Anat. : Cohn, 

 Sieb. and K61. Z. iii. 260 : Kolliker, Sieb. and Kol. Z. i. 198 : Claparede, Wiegm. 

 Arch. Dec. 1854, translated in Ann. Nat. Hist. 2 ser. xv. 211 : Schneider, ibid. p. 191, 

 translated ibid. xiv. p. 322 : Carter, Notes on the Infusoria of Bombay, Ann. Nat. 

 Hist, for 1856 and 1857 : A memoir by Dr. N. Lieberkuhn in Miiller's Archiv for 

 1856, translated in Ann. Nat. Hist, for Oct. 1856. 



