BACTERIOLOGY IN A NUTSHELL. 
Spirilla. 
Staphylococci. 
Streptococci. 
Diplococci. 
Tetrads. 
Sarcinae. 
Size of 
Bacteria. 
Spirals. 
The spiral-shaped are said some¬ 
what to resemble the twisted part 
of a corkscrew, and whether they 
have few or many curves, whether 
loosely or tightly twisted, the one 
name, “spirilla,” covers all of this 
variety. 
Modifications or subdivisions of the cocci have 
also been determined by watching their manner 
of forming into groups as seen in growing cul¬ 
tures. 
Staphylococci is the term used to describe those 
w r hich group in masses like grape-clusters. 
Streptococci, to describe those with method of 
grouping into chain-like sections. 
Other forms of the micrococci are found to 
group in pairs, and to describe these the term 
diplococci is used. 
Those which form into groups of four are 
called tetrads. 
Still another form is seen to make up groups 
of eight and sixteen, and to describe these we 
use the term sarcinae. 
There are two main subdivisions of the bacilli, 
namely: bacilli which are spore-forming, and 
bacilli which are non-spore-forming. By the 
term spores we mean seeds or eggs of the bacilli. 
All forms of bacteria are dependent upon cer¬ 
tain conditions for their development; these con¬ 
ditions are a certain temperature, proper soil, and 
in some instances air. 
Size of bacteria is a part of their description 
difficult to determine. So tiny are they that it is 
only under the highest power of the microscope 
that scientists are able to study them at all. One 
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