heart trouble. They fixed me up with one of those big jobs requiring my carrying batteries under my armpit."

"One of those early models. And this shows that at various times since then you have undergone replacive surgery some eighty-seven times, including three replacements of a pulmonary nature."

Again Lee hesitated. The number of times he had had a worn organ or tissue repaired or replaced was more than a little hazy. After the novelty of the first few times when he found himself with a new stomach, or liver, or muscle, he had started to take these things as a matter of course. He gave a little nervous laugh. "If that paper says so, I suppose so, doctor."

"Yes. Well, everything seems to be functioning properly now, doesn't it? With the exception of your head, of course."

"Yes, yes I feel fine otherwise." Lee was feeling uncomfortable. "Doctor, could you tell me what this is all about? I must have answered these questions half a dozen times before to those other people."

"In just a moment. First I need to know you a little better. Your medical history lists your occupation as 'cabinet maker'."

"That's right." Lee was becoming more and more uncomfortable. The extensive examinations had tired him, and repetition of the answers to all these questions was making him edgy.

"Doctor, can't you at least tell me what type operation I'm going to have?"

"What do you think it will be?"

"I don't know. Some sort of repair on my head, I guess."

"Mr. Lee, this isn't going to be a matter of repair. We have found it necessary to replace the entirety of what could roughly be called your 'brain', as well as part of the spinal cord."

"My whole brain?" Lee sat, stunned, comprehension slowly filtering into him. He voiced the only coherent thought which materialized. "Why that will mean there won't be anything left of me at all."

Dr. Letzmiller regarded him. "What do you mean?"

"Doc, you've got my records there. At one time or another, since they first put a new heart in me, every single inch of me has been replaced by an artificial part. I mean all of me. There's not one bit of me, heart, eyes, toenails, nothing, that is me. That bothered me quite a bit when this left eye was put in. I mean I thought, 'Well, this isn't me. This is my brain walking around in a jumble of artificial flesh.' I tell you it bothered me. But I went to a doctor, you know, a psychoanalyst, and he convinced me that as long as I had what he called a 'sense of identity', that I was me." Lee stopped. How could he explain it?

But Letzmiller seemed to understand. "And you think that your brain is all that is left of 'you'?"

"Doc, it's a funny feeling. Like this." Lee raised his hands, brought them together and touched his fingertips. "See that? I can raise those hands. I can make them touch each other. I can feel them touching each other. But it is just not quite right. It's just a little bit off key, like one trumpet player out of twenty being about one-sixteenth of a note flat. Know what I mean?"

"I think I do," said Letzmiller, nodding slowly. "Now, just what does that have to do with your operation?"

"Doctor—" Lee had to stop, for the patchwork quilt of blank spaces was dancing in his head. The helplessness went away, slowly, like smoke drifting from a fire. As his mind cleared, he realized that he didn't know why he was being interviewed by this doctor.

"Anything wrong?" Dr. Letzmiller asked.

Lee knew he wasn't being too coherent, jumping about with the conversation this way, but he asked the question, anyway. "Doc, why am I seeing you?"

"You haven't guessed?"

"No."

The doctor paused to light a half-gone cigar. "My job here at Merkins Replacive is to deal with just such fears as you have expressed. I'm an M.D. and a psychologist, and"—Letzmiller smiled to himself—"a kind of historian."

"Historian?"

"Well, you see I was supposed to give you the regular formal lecture on the history of