Marks , employed for classifying the Schizomycetes . 1 1 7 
difficult it was to put these three groups on the same 
footing. 
The further subdivision of the larger genera was based on 
the behaviour of the Schizomycetes towards the substratum — 
chromogenes, zymogenes, and pathogenes respectively — an 
idea started by Schroter and Cohn, and already partly 
employed by Winter and others, and one which has gained 
ground since. 
Van Tieghem seems to have relegated the characters 
derived from the method of spore-formation to quite a 
subordinate position, whereas De Bary, it will be remem- 
bered, elevates this into a diagnostic character of the highest 
importance. 
On the whole, we may regard Van Tieghem’s contribu- 
tions to the classification of the Schizomycetes as consisting 
in the recognition of the importance of the mode of division 
and the behaviour towards the substratum. In no other way 
can it be considered as an advance on Cohn and Ehrenberg’s 
system. 
Flugge, who has exerted considerable influence on the 
pathologists, especially in Germany, arranged the Schizomy- 
cetes in groups, much after the method of Cohn. I give his 
system in Table IV. 
TABLE IV.—. Flugge, 1886. 
I. Cells spherical or ovoid. 
A. Cells isolated, or merely seriate, or in amorphous aggregates. 
Micrococcus . 
B. Cells forming colonies more or less definitely circumscribed. 
(a) Colonies solid and entirely filled with the cells. 
(i) Colonies large, irregular, and numbers indefinite. 
Ascococcus. 
(ii) Colonies small, regular, and'numbers definite. 
Sarcina. 
(/ 3 ) Colonies excavated, with simple layers of cells at the 
periphery. 
Cohnia. 
