I'm not sure why, but a story I read many years ago recently popped into my head, and I have been agonizing over trying to figure out what it was ever since.
I believe it was in one of those "Best of the year" science fiction anothogies - maybe in the early 1990's.
The basic premise was that there was a space station with two living compartments. Every once in a while a single human would occupy one side and an alien would occupy the other. They didn't have physical contact with each other but they could sense each other's presence.
The human who was occupying the station was slowly being driven mad by curiosity about the alien who was so close, and I believe it was so stressful for the alien that it was secreting (or sweating) some substance that was of tremendous value to the human race.
Anyone have any idea what the name of this story is?
I would love to read it again and see if it is better than my vague memory of it. Thanks.