In years gone by, many children were afflicted with polio, measles, mumps, Rubella, influenza, small pox, diphtheria, whooping cough and others.
A recent small pox epidemic and the threat of attack by warring tribes created a fertile ground for fear and suspicion.
To protect you against small pox or diphtheria, you are vaccinated with a small amount of the toxin, and then your body develops immunity against that toxin.
Countless lives were saved from the ravages of diseases such as polio and small pox.