84 
WORLD OF INVISIBLE LIFE 
Does the effect 
of antitoxin 
last? 
the poison. Some of this blood is drawn from 
the horse’s veins. Then, when a child is in 
danger from diphtheria germs, some of the 
antitoxin is injected into his blood. Thus the 
child is protected against an attack of diph¬ 
theria. The same thing is done to protect 
people against typhoid fever, smallpox, and 
many other diseases. 
The protection given a human being by 
antitoxins taken from animals lasts only for a 
certain time, because the antibodies did not 
grow originally in his own blood-stream. But 
they do good work while they last, and they 
have saved many human lives, especially among 
little children. 
