CHAPTER III. 
REPRODUCTION OF BACTERIA. 
THE common method of reproduction among the 
bacteria is by binary division. In some forms this 
is the only mode of reproduction known. Under 
favorable conditions an individual cell grows in 
length, a transverse constriction appears in the 
middle and gradually becomes deeper until two 
new cells are formed. Separation may be com- 
plete or there may be the formation of chains. In 
the spherical forms division may take place in one, 
two, or three planes, forming chains (streptococci), 
or groups of two (diplococci), irregular groups 
(staphylococci or micrococci), or cubical packets 
(sarcina). In the rod-shaped forms division takes 
place in but one plane, forming chains, pairs, or 
single individuals (Figs. 9 and 10). 
Some bacteria, besides having the power of re- 
production by division, form endogenous spores. 
These spores are developed from the plasma of the 
cell, and have a dense wall that protects them from 
injury by drying, enables them to withstand high 
temperatures, and also causes them to resist the 
action of stains. 
I. Reproduction by Division. 
(a) On a clean cover-glass place a large drop of 
bouillon.' 
1 See page 50. = 
34 
