Here's my new vocabulary for the day: plombage. I actually learned that world in the course of doing a Google search on: tuberculosis lung "plastic balls".
What inspired that search was that I was visiting an older friend of mine today, who grew up in the South in the 1930s and 40s. She told us that she had had tuberculosis (TB) when she was born, which she got from her mother, who later died of the disease. I'll give away the punchline here by telling that my friend went on to live a happy, productive, and active life, despite having had the disease early in life, and despite the treatment she told about--the plombage.
Back in those days, treatments for TB were limited, and she was sent to a sanatorium to live for a while. According to this page I found when I came home afterward, the drugs she remembered--streptomycin ("a big needle, like this [hands a foot apart], every day!") and PAS--were discovered in 1944 and 1946 respectively. But before they had those drugs, they didn't have much else they could do about TB--it is an especially stubborn bacterium--so they tried lots of different things, some more extreme than others.
One of the things they tried experimentally was removing the diseased part of her lung, and filling the space with 24 small clear plastic spheres. She showed me a sample; it's about .75" (1.91 cm) in diameter, and very light. They put 24 of those in the space, and sewed her chest back up. (I tried to find a picture of the balls themselves in Google Images, but no luck.)
Apparently, the treatment made some people worse, and they had to open them up and remove the balls. My friend was luckier--like I said, she went on to recover and live (and still does) a very full, active energetic life, with home, family, friends, a career, and world travel.
But nowadays, very few people remember the bad old days of TB, and when she goes for an X-ray, she always causes a bit of a stir. The 24 plastic balls are still there in her lungs, and they show up as perfect circles on the X-ray. Every once in a while, she'll meet a doctor who knows of this, but most don't--and it amuses her to surprise them like that.