BACTERIOLOGY. 



A. Introduction to the Morphology of 

 Bacteria. 



By bacteria (spaltpilzen, schizomycetes of Nageli) 

 we understand a very large group of lower vegetable 

 organisms, morphologically very simple and uniform, but 

 biologically extraordinarily differentiated, which are so 

 connected with both the lower algse ^ and fungi by tran- 

 sition forms that a sharp separation by an accurate defini- 

 tion is difficult. Arthur Meyer emphasizes the relationship 

 of the spore-forming varieties to the ascomycetes, in which 

 the spore-forming cells appear as asci. Indeed, bacteria 

 bear a great resemblance to the simple flagellata, which 

 are usually conceived as animals. ^ 



The following definition may at least serve the practical 

 requirements of experimental bacteriology. 



Small unbranched ^ cells, rarely more than 2, hardly ever 

 3-5 /J. in thickness, almost * always without chlorophyl, spher- 



' Eeoently we have learned that the green lower algse also possess 

 parallel colorless forms, which can be obtained from them by cultures 

 (Beyertrick) ; compare also Liidwig, C. B. L. Il, 348. 



^ Compare Biitschli in Bronn's Klassen des Tierreiches, Bd. I, Abt. 

 II, Mastigophora. 



•'' Regarding the branching forms nearly related to bacteria compare 

 p. 19. 



* Practically, important bacteria with chlorophyl are unknown. 

 Yet the green tadpole bacillus (Kaulquappenbacillus) of J. Frenzel 

 must be recognized as a bacterium (Z. H. xi, 207). There is more 

 doubt as to the relation of Dangeard's Eubacillus multisporus to the 

 bacteria (C. B. x, 745). L. Klein described colorless varieties with 

 bluish-green spores (C. B. vil, 440). 

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