BACTERIOLOGY IN A NUTSHELL. 
Authorities 
Differ. 
Channels of 
Entrance. 
Period of 
Incubation. 
Why 
Multiplication 
Ceases. 
It must be borne in mind, however, that author¬ 
ities differ as to the mode of entrance of some of 
the bacteria and that theories change as new light 
is thrown on the- subject. The science of bac¬ 
teriology is still rapidly progressing. 
The alimentary canal, the respiratory tract, the 
genital tract, the mucous membranes, wounds 
and the skin, all form channels whereby infection 
is conveyed to the various parts of the body 
which are seats of attack for pathogenic bacteria. 
An incubation period, which varies, in duration, 
is common to all forms of disease caused by the 
invasion of bacteria. During the incubation pe¬ 
riod there are no symptoms of the disease' The 
germs have gained admission to the body by one 
or other channel of entrance and a war is being 
waged between the invaders and the antagonistic 
cells already spoken of as phagocytes. Under 
favorable circumstances the invaders do no harm, 
they are destroyed by their foes and are thrown 
off from the body in the excretions. If the pow¬ 
ers of resistance are weakened in any way, by the 
presence of any other disease, for instance, the 
influence of the phagocytes is lost and the period 
of incubation ends in another period wherein the 
power of the invading bacteria is made manifest 
and symptoms arise followed by more or less 
serious results. 
In each specific disease the infection is thrown 
off from that part of the body which is the seat 
of the invasion. 
During the course of a communicable or spe¬ 
cific disease there comes a time when there is no 
longer any suitable nourishment for the growth 
and development of the micro-organisms and then 
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