82 
WORLD OF INVISIBLE LIFE 
What do the 
white corpuscles 
do? 
Scarlet fever 
antitoxin 
rounded by the body of a white corpuscle and 
absorbed into it and digested. The white 
corpuscles really eat the microbes. Sometimes, 
however, the microbes are too numerous for 
the white corpuscles, or grow faster than the 
white corpuscles can eat them; then the 
microbes spread through the body and cause 
illness. These white corpuscles are always on 
guard in the body and are constantly at work 
destroying the harmful microbes that are trying 
to attack it. As long as the white corpuscles 
are stronger in the fight, and kill the microbes 
faster than they grow, we do not become ill. 
An invasion of microbes in large enough 
numbers to produce illness causes the body to 
make other special efforts to fight them. It 
has been found that the coming of any kind 
of microbe into the body is the signal for the 
appearance, in the blood and tissues, of sub¬ 
stances that are able to kill that kind of microbe 
and make the poison it produces harmless. 
The blood and tissues having this power to 
fight a special microbe are said to contain things 
