CLASSIFICATION. 17 
is scarcely to be considered of practical value, inasmuch as the ques- 
tion of spore formation is still undetermined for a large number of 
species. 
In the following table we shall give the characters of the dif- 
éerent genera which have been described by recent botanists and 
bacteriologists, arranged under the three headings, Micrococct, 
Baciuui, SprRiLya. Where we doubt the propriety of maintaining 
a distinct generic name upon the supposed distinguishing characters, 
the description will be printed in small type. 
MICROCOCCL. 
General Characters.—Spherical bacteria which are reproduced 
by binary division ; usually without spontaneous movements ; do not 
form endogenous spores. (According to some authors, certain cells, 
known as arthrospores, may be distinguished by their greater size 
and refractive power, and these are supposed to have greater resist- 
ance to desiccation than the ordinary cocci resulting from binary 
division, and to serve as reproductive bodies.) Some micrococci are 
not precisely round, but are somewhat oval in form; and when in 
process of division the cocci, necessarily, are more or less elongated 
in one diameter before a complete separation into two spherical ele- 
ments has occurred. 
Micrococcus.—Division in one direction ; cocci single, in pairs, 
or accidentally associated in irregular groups ; sometimes held to- 
gether in irregular masses by a transparent, glutinous, intercellular 
substance. (Micrococci belonging to this genus are frequently de- 
scribed as ‘‘ staphylococci,” and Staphylococcus is used by Rosen- 
bach as a generic name for the pus cocci described by him, which 
are solitary or associated in irregular groups, as above described.) 
Ascococcus.—Cocci associated in globular or lobulated, zoéglea 
masses by a rather firm intercellular substance. 
LEeuconostoc.—Cocci, solitary or in chains, surrounded by a 
thick, gelatinous envelope and forming zodgloea of cartilaginous 
consistence. 
STREPTOCOCCUS.—Division in one direction only ; cocci associ-_ 
ated in chains. 
Diplococcus.—Division in one direction only ; cocci associated in pairs. 
Association in pairs is common to all of the micrococci, inasmuch as 
‘they multiply by binary division. When such association has rather a per- 
manent character, it is customary to speak of the microdrganism as a diplo- 
coccus, but we doubt the propriety of recognizing this mode of association 
as a generic character. 
MERISMOPEDIA.—Division in two directions, forming groups of 
four, which remain associated in a single plane—“ tetrads.” 
SaRcInA.—Division in three directions, forming packets of eight 
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