sea PHYSIOLOGY OF THE BACTERIA. 
be found to occupy the entire field of the micro- 
scope. From this moment the phenomena which 
occur differ according to the conditions in which 
the bacteria are placed. Upon the edge of the 
air-groove in the moist chamber, the bacteria de- 
velop very rapidly, forming an interlaced mass; 
and in sixteen to eighteen hours, spores may be 
seen to appear in their interior, — above all, if the 
preparation has been exposed to light. Often, in 
this case, the transverse partitions of the filament 
cannot be seen. IH, on the contrary, the bacterium 
has not been exposed to light, the spores are a 
longer time in showing themselves (ten or twelve 
hours more), and almost always division of the 
filament precedes their formation. In that case, 
a spore usually appears at each end of the seg- 
ment in such a manner that the spores belonging 
to two successive segments are nearer to each 
other than those in the same segment. Often, 
also, a spore aborts in a segment (Toussaint). 
We have seen above, in speaking of the res- 
piration of bacteria, that the same observer has 
noted in the course of his experiments some phe- 
nomena proving the evident influence of oxygen 
upon the development of Bacillus. It is the same 
for the formation of spores. And upon this point 
Toussaint makes the very just remark that the 
phenomena occur in a different manner in culture 
experiments and in the human organism. In char- 
bon, the bacteria never form spores. They remain 
always relatively short, even in the points where 
they form extra-vascular masses, and where conse- 
