Dr. Beak

Plague doctors wore a mask with a bird-like beak to protect them from being infected by the disease, which they believed was airborne. In fact, they thought disease was spread by miasma, a noxious form of  “bad air “. To keep away bad smells, the beak could hold dried flowers including roses and carnations, herbs, spices, camphor, or a vinegar sponge

The reproduction number (R) is the average number of secondary infections produced by a single infected person

An R number of 1 means that on average every person who is infected will infect 1 other person, meaning the total number of infections is stable. If R is 2, on average, each infected person infects 2 more people. If R is 0.5 then on average for each 2 infected people, there will be only 1 new infection. If R is greater than 1 the epidemic is growing, if R is less than 1 the epidemic is shrinking

www.gov.uk, wikipedia

Copper engraving of Doctor Schnabel – Dr. Beak, a plague doctor in seventeenth-century Rome, circa 1656