Call the Midwife - Those who watched our Christmas Special will have seen a major story strand involving the scourge of polio, and treatment involving a machine called a negative pressure ventilator -
![Living inside a canister: Dallas polio survivor is one of few people left in U.S. using iron lung - YouTube Living inside a canister: Dallas polio survivor is one of few people left in U.S. using iron lung - YouTube](https://i.ytimg.com/vi/9kEFTmyM1tc/maxresdefault.jpg)
Living inside a canister: Dallas polio survivor is one of few people left in U.S. using iron lung - YouTube
![Iron lung (c. 1933) used to "breathe" for polio patients until 1955 when polio vaccine became available is located in the Mobile Medical Museum, Mobile, Alabama | Library of Congress Iron lung (c. 1933) used to "breathe" for polio patients until 1955 when polio vaccine became available is located in the Mobile Medical Museum, Mobile, Alabama | Library of Congress](http://tile.loc.gov/image-services/iiif/service:pnp:highsm:05200:05216/full/pct:50/0/default.jpg)