There are two sorts of plague:
The first was carried by the fleas on rats. The symptoms were horrible. First of all big black swellings called buboes appeared in the armpits and groin of the patient. These bled and leaked pus.
Boils and black patches appeared all over the victim. Perhaps this is why it became known as "The Black Death". People usually died of it in about five days.
The second was carried by coughs and sneezes. This made the victims cough and sweat and they could die in as little as 24 hours after catching it.
The doctor could not cure the plague but there were three ways he could try. (On the left).
There were other diseases he could not cure.