“ Human beings were meant to leave in open, guard by the prophylactic of sunshine and pure air. There is alway damage of contagion in crowds - in factories, elevators, street cars, theaters.
... In every crowd there are almost certainly several ‘carriers’ of disease germs.
… How many 'Typhoid Marys' are in this crowd?”
Title: Crowds Breed Contagion
Date: 1923
Company: Lever Brothers Company
Product: Lifebuoy Health Soap
Publication: Saturday Evening Post
Digital Collection: Ad*Access duke:335102
https://worldofwonder.net/bornthisday-medical-pioneer-sara-josephine-baker/