94 
HOUSEHOLD BACTERIOLOGY 
Antitoxine 
Acquired 
Immunity 
Vaccination 
It seems, then, probable that in the blood serum of 
immune persons there may be another factor in the 
vital resistance. That is, the body cells in some way 
manufacture substances that neutralize the poisons or 
toxines produced by the germs, thus enabling the body 
to expel the germs themselves, and recover. These 
cintitoxines or the power of producing them may re¬ 
main and the body becomes immune to the disease. 
These antitoxines are specific in nature,—that is, are 
capable of neutralizing the toxine of only one kind of 
germ. 
Immunity may also be “acquired” by the injection 
into the blood, in some cases, of the germs themselves, 
as in the case of inoculation for small pox as was 
as was originally done in the case of inoculation for 
small pox. Formerly some “matter,” that is, the in¬ 
fectious material, was taken from a person sick with 
small pox and injected directly into another person by 
placing it under the skin, where it quickly afifected the 
whole body. 
Jenner—a celebrated doctor in England about 1796 
—first modified inoculation by introducing the “mat¬ 
ter” into healthy calves or cows. These animals be¬ 
ing very susceptible to the disease, contracted it, and 
then from the pustules of their bodies the “matter” 
or “vaccine” was drawn and injected into human be¬ 
ings. This, in man, was found to produce a milder 
form of the disease and to leave in the system upon 
recovery something which gave immunity or protec¬ 
tion from small pox. 
