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PRINCIPLES OF BACTERIOLOGY 
Protected from sunlight the tetanus spores will live 
for years. 
V. Disease Production, Mode of Infection, Disinfec¬ 
tion and Prophylaxis 
The tetanus bacilli are found in superficial layers of 
soil, especially near stables and manured fields. 
Bacillus tetani produce a disease called lockjaw, char¬ 
acterized by convulsions and closing of the jaws. Deep 
lacerated wounds where there is much tissue destruction, 
as, for example, gun-shot wounds, are especially favor¬ 
able for the development of the tetanus. 
The true prophylaxis consists in administering anti- 
tetanic serum in all gunshot wounds, or where the patient 
had stepped on a nail, especially near the tilled soil. 
VI. Mechanism of Infection and Immunity 
The tetanus bacillus produces an exotoxin, which has 
a special affinity for the nervous system. It is one of 
the most poisonous substances known, one-millionth of a 
gram being sufficient to kill a mouse. 
The common fowl is extremely resistant to tetanus, 
while the man and horse are unusually susceptible. 
The animal injected with nonfatal doses of tetanus 
produces an antitoxin as the only antibody. 
VII. Bacteriologic Diagnosis 
Bacteriologic diagnosis is easy and consists in finding 
a Gram-positive, “ drumstick ’’ like spore-bearing bacil¬ 
lus; culturally it is an anaerobe, growing well on meat 
infusion media. 
