Neat, wofa, thanks. I can't remember what I've read by James Blish, but I know I liked it. This story reminds me of one (title, author completely forgotten) about some scientists (?) trying to find out why their emissaries/scouts kept disappearing instead of reporting back their findings as they were supposed to. Finally it turns out that, to prepare for the exploration, they have to physiologically adapt to that world, and they all loved the joyous freedom of the jaguar-like creatures they became too much to be bothered going back to report.