CLASSIFICATION, MOVEMENT AND GROWTH. 137 
What are flagelle ? 
They are little thread-like processes or cilia running out from some 
of the different varieties of bacteria. They have a whiplike motion 
and are in a constant state of activity. A very few varieties of micro- 
cocci have been proved to possess flagellee. 
To what has the term zoogleea masses been applied ? 
To any irregular mass of bacteria which is made up of one single 
kind or colony of a given variety. 
Do bacteria possess the power of motion ? 
The rod-shaped forms or bacilli and the spiral-shaped forms or 
spirilli possess this power, and in some varieties it has been proved to 
be due to the action of flagella growing from them. 
A few varieties of micrococci have the same power of motion, and 
they also have been shown to have flagella. Most varieties of 
micrococci, however, do not have the power to move from place to 
place. . 
What is the “‘ Brownian movement ”’ ? 
Very often micrococci and also small particles of inorganic matter 
when suspended in a fluid media between two glasses have an oscillating 
movement, but it does not serve to propel them about, as they always 
remain in the same place. This is called the Brownian movement. 
How do the micrococci grow ? 
They grow by simple fission, that is, one of the organisms becomes 
elongated in one direction and appears at first to be slightly indented at 
the sides. These indentations become deeper and deeper until the 
organism divides into two. They may stick together as diplococci, and 
each dividing form four cocci or atetrad. The process may go on irreg- 
ularly in all directions and in that manner form irregular masses or 
staphylococci. When the segmentation continues in one direction, then 
long chains or streptococci are formed. 
How do bacilli grow ? 
In just the same manner, by fission, but the segmentation always 
occurs in a direction parallel to the long axis of the organism, and 
never longitudinally. 
How do the spirilli grow ? 
It is supposed that they grow and increase in the same manner. 
Their mode of growth however is not well understood. 
