CLASS I. 

 INFUSORIES (INFUSORIA). 1 



THESE animals are called Infasories 2 , because they are to be 

 found in infusions of every kind of organic matter, as well vegetable 

 as animal. Moreover they live in all stagnant marshy waters, and 

 even in running waters, salt and fresh. 



These animals, which on account of their minute size can only 

 be discovered, or at all events examined, by means of magnifying 

 glasses, were unknown to the ancients. Our LEEUWENHOECK first 

 saw them in infusions towards the end of the seventeenth century 

 (1675). After LEEUWENHOECK, many species of these animals 

 were observed and described in the last century by EOESEL, LEDER- 

 MUELLEE, VON GLEICHEN and others : but more especially O. F. 

 MUELLER, the Danish naturalist, in a work which appeared after 

 his death, figured many species, and gave a systematic arrangement 

 of the class. In the present century, EHRENBERG has contributed 

 most largely to our knowledge of infusories, and since 1828 has 

 from time to time published his investigations in the Transactions 

 of the Berlin Academy of Sciences, and more recently has collected 

 them into a body in a large illustrated work. 



As the discoveries of astronomers allow us to cast a glance into 

 the illimitable extent of space of the universe, so the eye, artificially 

 strengthened, affords conviction of the illimitable distribution of 



1 The chief works relating to this class are : 



O. F. MUELLER, Animalcida infusoria fluviatilia et marina. Hauniae, 1786. 4to. 

 The Plates are copied in the Encyclopedic meihodique. 



C. G. EHRENBERG, Die Infusionsthierchen, ah vottlcommene Organismen. Nebst einem 

 Atlas von 64 colorirten Kupfertafeln, Leipzig, 1838 folio. (G. VALENTIN gave in his 

 Repert orium filr A not. und Physiol. iv. Bd. Jahrgang, 1839, a detailed abstract of 

 this work, containing the characters of all the genera and species, s. 136 181.) 



Histoire naturette des Zoophytes. Infusoires, comprenant la Physiologie et la Classifi- 

 cation de ces Animaux, par F. DUJARDIN, Paris, 1841. 8vo. 



Die Infusionsthiere auf ihre Entwickelungsgeschichte untcrsucht von DB FBIEDRICH 

 STEIN, mit 6 Kupfertafeln. Leipzig, 1854. 4to. 



2 First by LEDERMUELLER, according to EHRENBERG. 



