A. Introduction to the Morphology of 

 Bacteria. 



By the term bacteria (schizomycetes of Naegeli) is 

 meant a very large group of the lowest vegetable or- 

 ganisms, which are morphologically very simple and 

 uniform, but biologically are extremely differentiated. 

 They are related to the lowest algae (phycochroma- 

 cea) and the lowest fungi by so many intermediate 

 forms that a strict separation by a rigid definition 

 appears difficult. Various bacteria also exhibit great 

 similarity* to the simplest flagellates, which are usu- 

 ally regarded as animals. 



A definition is rendered more difficult by the fact 

 that botanical investigations of bacteria are compara- 

 tively rare, and that we still possess very imperfect 

 knowledge concerning various details in the struc- 

 ture of bacteria (ramifications, separately stained 

 parts f). 



* Vide Biltschli in Bronn's "Klassen des Tierreiches, " vol. i., 

 part ii., Mastigophora. 



f It is to be noted, moreover, that according to Bref eld's my- 

 cological investigations (vol. viii., p. 274), forms develop dur- 

 ing the process of development of higher fungi which possess a 

 striking resemblance to bacteria during many successive genera- 

 tions. We must therefore concede the possibility that among 

 the varieties of bacteria a number do not deserve the term 

 " species, " but belong to the category of other fungi. 

 5 



