CLASSIFICATION OF BACTERIA. 
9 
Bacteria reproduce by what is known as binary 
fission; that means a pinching off or splitting in the 
middle, each part developing into another organism. 
Reproduction occurs only under conditions favorable 
for bacterial growth. The rate of division or multipli¬ 
cation as very fast, sometimes every fifteen minutes. 
Starting with one organism one can imagine what an 
enormous number may develop in twenty-four hours 
at this rate. 
Under conditions unfavorable to the life and 
growth, some kinds of bacteria may assume another 
form to avoid extermination. This is called spore 
formation. These spores are round or oval bodies, 
much smaller than the organisms from which they 
originate, and differ from them in having a thick pro¬ 
tective capsule that enables them to withstand heat, 
sunlight, and, in fact, any harmful influence. The 
spores may be formed inside the body of the organism 
and extruded from it, or the whole organism may be 
changed into a spore. As a rule, one forms in each 
organism, either in the center or at one end, but in 
some kinds of bacteria a spore may form at each end. 
When conditions again become favorable for growth 
the spore may elongate and gradually assume its 
original shape, or the bacillus may form inside the 
body of the spore and burst the capsule. 
The power of locomotion is observed in some 
bacteria. When watched under the microscope they 
may be seen moving across the field of vision. The 
motility depends upon small, thread-like processes pro- 
Repro- 
duction 
Spore 
forma¬ 
tion 
Motility 
