302 APPENDIX. 
to this nomenclature, which appears to be adopted by 
histologists, so as not to overload the synonymy of 
‘microbes, which is already somewhat encumbered. It is 
probable, moreover, that this assimilation is correct, 
and that most bacilli pass through a phase in which they 
are short and mobile, before becoming elongated and 
stationary. On the other hand, certain types of the old 
genus Bacterium—for instance, the bacteria in the form of 
an 8—should rather be assigned to the genus Micrococcus, 
or to the new genus Diplococcus. 
With respect to the genus Vibrio, it seems to have 
been originally only a somewhat heterogeneous collection, 
comprising both the chains and chaplets of micrococci or of 
short bacteria, and the strictly unicellular organisms which 
might be assigned to the genus Spirillum. Klein, how- 
ever, reserves this genus for Vibrio rugula and V. Serpens. 
The genus Micrococcus (Hallier) is also termed by 
Cohn, Spherobactertum, and these two names are now 
given to the only unicellular microbes which are round 
or oval, stationary, and consequently devoid of cilium or 
flagellum, the organ of propulsion. 
These micrococci may be in the form of chains or 
chaplets (torula), dumb-bells (Klein), the figure 8 (Diplo- 
coccus, Billroth), groups of four, and zoogloes or in masses 
of greater numbers. 
The genus Bacterium (Microbacterium, Cohn) differs 
from the foregoing, as Klein states, chiefly in the oval or 
cylindrical form of its cells, and still more by the presence 
of a cilium or flagellum at one extremity, which gives a 
spontaneous movement. They may thus assume the form 
ot a sponge-cake and of a dumb-bell when they divide in 
two, and may also form short chains or zoogloes, As we 
have already said, most of these organisms are assigned 
