INFUSORIA AND OTHEK ANIMALCULE. 239 



sen and his son Zacharias Jansen of Middleburg, 

 revealed to us the existence of myriads of living 

 creatures, of whose presence in nature we had not 

 before the slightest suspicion ; and observation has 

 disclosed a number of organic creations comparable 

 only to that of the stars revealed by the teles- 

 cope. When Linnaeus arranged all the organized 

 beings known to him in his ' ' Systema Naturae," 

 the structure of infusoria and other animalcules was 

 not sufficiently known to enable him to distribute 

 them properly. He therefore placed them at the 

 end of his last class, Vermes, in a genus which he 

 denominated Chaos. 



Othon Frederic Miiller first distinguished them 

 as a distinct order, and finding they were so quickly 

 produced in infusions of vegetable substances, 

 called them Infusoria. Miiller's work was published 

 in 1773-4. He described many species. But 

 Needham had already published (1745) his "New 

 Microscopical Discoveries." 



These minute organisms have also been investi- 

 gated by Leuwenhoek, Lamarck, Cuvier, Bory de 

 St. Vincent, Hill, Hooke, Adams, Baker, Spal- 

 lanzani, Ehrenberg, Mantell, Pritchard, Morren, 

 Pouchet, etc. 



Ehrenberg studied their internal structure by 

 feeding them on colouring matters, such as indigo, 

 and carmine. 



