1 1 8 Marshall Ward,— On the Characters , or 
II. Cells cylindrical. 
A. Cells as short rodlets ; isolated, or aggregated into loosely 
united or gelatinous families. 
Bacterium . 
B. Cells several or many times longer than broad, and united into 
filaments. 
(a) Filaments isolated, or matted together, or in fasciculi. 
(i) Filaments not branching. 
* Filaments straight. 
t Filaments short and distinctly segmented. 
Bacillus. 
t t Filaments long and segments indistinct. 
Very thin. 
Leptothrix . 
Thicker. 
Beggiatoa. 
* * Filaments undulate or spiral, 
t Short and rigid. 
Spirillum ( Vibrio ), 
t t Long and flexile. 
Spirochaete. 
(ii) Filaments with false ramification. 
Cladothrix (Streptotkrix). 
(j3) Filaments enveloped in rounded gelatinous matrix, 
Myconostoc, 
The chief advance here, in addition to the expurgation of 
certain genera no longer admitted as Schizomycetes, is the 
greater clearness in definition of the forms, gained partly by 
the fusion of trivial genera, and partly by the expression of 
the diagnostic characters. Nevertheless, Fliigge's modifica- 
tion of Cohn’s system suffers from the same defects as Van 
Tieghem’s and the other older schemes, namely, that the forms 
selected as types are often only form-genera, and we un- 
doubtedly meet with transient phases of one and the same 
filamentous genus which would be placed in two or more 
genera if such a system were rigidly followed. 
Hueppe, whose book on methods, especially, has deservedly 
attained a world-wide reputation, has proposed a scheme 
