A year or so before the colonoscopy, my own doctor performed a sigmoidoscopy on me in his own office. The colonoscopy, I gather, is trickier, with more inherent risks, takes longer and goes farther; it requires a surgeon, I believe.

In my case a diaphramatic hernia repair was scheduled; as my surgeon said, she didn't want any surprises and scheduled a colonoscopy beforehand.

I had been told that, given the sedative, I would probably sleep through the procedure and in any event would be unlikely to remember any part of it. I don't know if they gave me less sedative than usual. I was relaxed but watched the whole thing on the monitor.

At one point I had been watching in silence as the thing traveled and then asked a question about a bend in the 'tube'. The two doctors seemed startled and said something like 'You're still awake!'