THE MICROBES THAT MAKE US SICK 71 
to fight againts diphtheria germs that have been 
placed in their bodies. This will kill the germ 
in a human being who has the disease. It is 
forced into the tissues below the skin with a 
syringe, is absorbed by the blood, and attacks 
and kills the germs in the throat. 
The germ of pneumonia is round, but with 
a pointed end. It looks like a comma (,) and 
usually grows in pairs, sometimes in chains. 
There are some of them in nearly everyone’s 
mouth and throat, but they do not attack the 
lungs and cause pneumonia except in certain 
cases. Perhaps the person’s body has been 
weakened by some illness like measles or 
typhoid fever; perhaps the circulation of the 
blood is upset by a long or sharp exposure to 
severe cold, or perhaps the body has been 
weakened by some other cause. Then the 
pneumonia germ can do its deadly work. 
Babies and old people are more liable to get 
the disease than anyone else, because they are 
so often not strong enough to fight off the 
germ’s attack. It usually attacks only the lungs, 
What is 
antitoxin? 
