TAXONOMY 
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( b ) Cell-division in gonidial formation in three directions 
of space — Streptothrix. 
*Marine forms with cells surrounded by a very delicate 
hardly discernible sheath — Phragmidiothrix. 
**Fresh-water forms with easily discernible sheath — - 
Crenothrix. 
2. Filaments branched. 
B. Cell contents with sulphur granules — Thiothrix. 
Family VI. — ^Beggiatoaceae. — Thread-like, without a capsule, but 
with an undulating membrane. Cell contents show sulphur granules. 
A. Threads apparently not septated, septa only faintly visible 
with iodine staining. Colorless or faintly rose-colored — Beggiatoa. 
Sporulation. — A large number of bacteria possess the power of 
developing into a resting stage by a process known as sporulation 
or spore formation. Sporulation is regarded as a method of resisting 
unfavorable environment. This is illustrated by the anthrax 
bacilli which are readily killed in twenty minutes by a 10 per cent, 
solution of carbolic acid, and able, when in the spore condition, to 
resist the same disinfectant for a long period in a concentration of 
50 per cent. And, while the vegetative forms show little more 
resistance against moist heat than the vegetative form of other 
bacteria, the spores will withstand the action of live steam for as long 
as ten to twelve minutes or more. 
Whenever the spores are brought into favorable condition for 
bacterial growth, as to temperature, moisture and nutrition, they 
return to the vegetative form and then are capable of multiplication 
by fission in the ordinary way. 
Reproduction.- — Bacteria multiply and reproduce themselves by 
cleavage or fission. A young individual increases in size up to the 
limits of the adult form, when by simple cleavage at right angles to 
the long axis, the cell divides into two individuals. 
Morphology Due to Cleavage. — According to limitations imposed 
by cleavage directors, the cocci assume a chain appearance, or a 
grape-like appearance, or an arrangement in packets or cubes having 
three diameters. This gives rise to the 
Staphylococcus (plural, staphylococci), from a Greek word referring 
to the shape of a bunch of grapes. 
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