That’s the mystery two researchers are working on in this photo from the April 1940 issue of Popular Science:
Infectious germs are spouted from the mouth of a mechanical sneezer developed for medical research by William F. Wells of the University of Pennsylvania medical school in Philadelphia. By means of compressed air, the apparatus blows air-borne germs through a tube into a glass bell housing an experimental rabbit, to simulate the common method of transmission of germs by human sneezers and coughers.
Hey, it only took us 73 more years to invent a barfing machine! Now that’s progress.