https://www.bloomberg.com/news/articles/2020-08-05/the-curio...
The “spent breath” of the occupants of poorly ventilated homes contributed to 40% of the deaths in the country, he claimed, and often said “man’s own breath is his greatest enemy.” He would spend decades promoting the cause, designing ventilation schemes for buildings, penning a 1869 book, Leeds on Ventilation, and lecturing across the country. He explained his ideas with the aid of a “magic lantern” projector — think old-timey Powerpoint presentations. He’d show slides of a family in their drawing room, then add a slide showing red air coming out of the father’s mouth. The child crawling on the floor would eventually fall over. It “scared people to death,” Holohan says.
https://www.npr.org/2020/12/10/945136599/how-spanish-flu-pan...