This disease, also known as Pest or the bubonic plague, was a vicious infectious disease that decimated medieval Europe. It is caused by the bacteria Yersinia pestis, usually transmitted by fleas. The symptoms vary from high fever, malaise, nausea and vomiting, headaches, muscle cramps, seizures, red rashes, coughing and swollen lymph nodes, and causes death within four or five days without treatment.
People did not know about the existence of bacteria back then (it would be 200 more years until Louis Pasteur would suggest germs as the cause of infections). Back then, they considered diseases to transmit through miasma, or bad air. Also, they believed that to prevent transmission, they required a stronger smell to counter it.
Plague doctors, who treated according to the miasma theory of disease, wore a special set of equipments that were known as beak doctor costumes. They wore an overcoat, hat, gloves and boots made from waxed leather, carried a cane to assess the patient and point things out, and a peculiar mask. The mask had a long beak like a bird’s, giving the doctors the nickname beak doctors. The masks had round, glass windows to see through, and two small nostrils at the end of the beak.
Why did they wear this strange mask? The beak was hollow and doctors filled it with flowers, herbs, vinegar and incense that produce a strong smell, so as to “purify” the air coming through the nostrils.
Although the miasma theory has been falsified by germ theory, this gear was the first hazmat suit in history.
There is another fascinating fact regarding the Plague, miasma theory and beak doctors. It regards the nursery rhyme, Ring a Ring o’ Roses:
A pocket full of posies;
We all fall down.
This nursery rhyme actually describes the Plague. The ring of roses refers to the red rashes and swelling of lymph nodes – a symptom of the Plague; the posies were herbs used to counter the miasma; coughing and sneezing were end-stage symptoms before death, which is shown in the final line.