"Well," said Heidel, "I suppose you could put it that way. But it is oversimplifying. With proper preparation I can effect the cure of almost any disease, if the patient is not too far gone. On the other hand, my own condition is not a completely one-sided thing. It might be more appropriate to say that I am a living pool of diseases which I can bring into a sort of balance. When that balance is achieved, I can act as a remedy. Only then, though. The rest of the time, I can be very dangerous."

Dr. Helman plucked a dark string from his sleeve and deposited it in the ashtray. Heidel smiled at this, wondering how he must look to the doctor.

"But there is no indication as to the mechanism involved?"

"Nobody seems to be certain," Heidel said, finally lighting the cigar. "I seem to find diseases wherever I go. I contract them, then some sort of natural immunity seems to stave off the worst of the symptoms and I recover. Thereafter, under the proper circumstances, a serum made from my blood is effective against the same condition in someone else."

"What, specifically, are the preparations, the circumstances you speak of?"

"I go into a coma," Heidel began, "which I can induce at will. During this time, my body does something which seems to purify it. This takes anywhere from a day and a half to several days. I am told--" He paused here, quickly drawing upon his cigar. "I am told that during this time my body undergoes frightful symptoms from all the diseases I carry. I don't know. I never have any memory of this. And I have to be alone at such times, as my diseases then become quite contagious."

"Your clothing--"

"I disrobe first. My body carries nothing when I awaken. I change clothes afterward."

"How long does this--balance--last?"

"Usually a couple days, and then I revert--slowly. Once the balance is destroyed I become progressively dangerous again. I become a disease-bearer until the next catharsis-coma."