"You have been convinced, at least in one essential, of the truth of this story. You must be able to see why the secret has been kept so far and the risk we chose to face in telling you. There is certainly a chance, however small, that you are actually the person harboring our quarry.
"In that event, we see two possibilities. Either you know of his presence and are consciously co-operating with him because he has convinced you of the justice of his position, or you do not know. In the first case, you are now planning means to get rid of me. Your guest would be perfectly willing to do anything to my host in the process, but I know you would not; and that presents you with a problem that will take time to solve and will probably betray the truth to me in your attempts to solve it.
"In the second case, Doctor, your host now knows where I am. He also knows that you are a doctor, and will find some means to detect his presence in your body if anyone can. That, I fear, will mean that we have placed you in danger, for he will have no hesitation in doing whatever he thinks necessary to escape. I cannot suggest any precautions to you; you should be able to think of some yourself. Don't mention them aloud, though.
"I am sorry to have exposed you to this risk, but it seems to me to be one that falls within your normal duty as a doctor. If, however, you are not willing to take it, simply say so. We will leave at once. We will, of course, test you at the first opportunity; but with the fear of immediate discovery no longer pressing, he may at least leave your body without harming you, since he will be in no hurry. What is your decision?"
Dr. Seever did not hesitate an instant.
"I'll take any risks there may be. I think I can see how to test myself too. According to your story, you have been in Bob's body nearly six months; and your quarry, if he is in mine at all, is likely to have been there for several weeks at least. That is long enough for the formation of specific antibodies-you say you are, in effect, a virus. I can make a serum test with a sample of Bob's blood and my own that should give us an answer at once. Have you learned enough medical English to gather what I mean?"
Bob replied slowly, reading off the Hunter's answer as it came. "I know what you mean. Unfortunately, your plan won't work. If we had not long ago learned how to prevent the formation of antibodies for our particular cells, our way of life would never have been possible."
The doctor frowned at this. "I should have thought of that. I suppose there's no use expecting your friend to let any of his own tissue be caught in a section or a blood sample, either." He looked up sharply. "How did you plan to make identification? You must have some method."
Bob explained the Hunter's difficulty in that direction, then the alien finished: "I intended, when reasonably certain, to make a final check by personal inspection. He certainly could not hide for any length of time if I went into the same body in search of him."
"Then why not check me that way? I know you have no particular reason to suspect me, but it would be just as well to know one way or the other. You would know then that you could trust me; and, frankly, I should like to know myself. I've been rather afraid these last few minutes that I might find out the hard way as soon as you two leave the office."
"Your point is a good one," relayed Bob. "But the Hunter will not enter or leave any human body while its owner is awake. You seem to sympathize with him on that." The doctor nodded slowly, looking thoughtfully at his visible guest.
"Yes. Yes, I understand his reason. However, that situation can be arranged also." Dr. Seever left his chair and went to the front door, taking a small placard from a wall stand as he passed it. This he placed on a hook outside the door, closed and locked the latter, and returned to the office. He looked at Bob again, then went over to one of the numerous small cabinets.
"How much do you weigh, Bob?" he asked over his shoulder. The boy told him, and he made a brief calculation in his head, then he reached for a bottle of clearliquid. With this in his hand he turned back to the visitors.
"Hunter, I don't know whether this stuff will affect you as well. I would suggest that you get out of Bob's alimentary and circulatory systems before we take it. We will sleep for from one to two hours-I suppose that's longer than necessary, but I can't guarantee that any smaller dose would put us out at all. You can make your test while we're unconscious and get back to tell us the result-or maybe do something else, if necessary. All right? We won't be disturbed-I've seen to that."
"I'm afraid it is not quite all right," was the answer. "It means that my host would be helpless before I know for certain about you. However, I will concede that the test should be made, and I will relax my demand somewhat to get it over with. If you and Bob will sit side by side, holding hands tightly, and guarantee that you will not separate those hands for twenty minutes, I will shift • enough of myself into your body to make the inspection and return."
The doctor agreed instantly-he had intended to use the drug only because of the Hunter's insistence that the hosts be insensible, and this alternative was both safer and pleasanter. He moved his chair out beside Robert's, therefore, took one of the boy's hands in his own, dropped the bandage that had served as a blindfold over the two hands as an added safeguard for the Hunter's peace of mind, and relaxed.
It took a little more than the promised twenty minutes, but to their relief the Hunter was able to give a negative report. Discussion for the first time flowed freely-at least between Bob and the doctor-and the general conditions of the problem were thrashed over so thoroughly that Dr. Seever almost forgot about Bob's injured leg. It was only at the end of the visit that he mentioned it.
"As I understand it, Bob, your friend can do nothing to speed up the processes of healing; he simply prevents bleeding and infection. My advice is to stay off that leg- you gave the muscle an awful beating."
"The only trouble is," said Bob, "I seem to be transportation division for this army and am vehicle for the commander in chief. I can't be immobilized."
"Well, it will certainly slow up the healing; I can't see that any other damage will result, under the circumstances. Use your own judgment; I know the situation is serious for someone. Just keep off it as much as possible." The doctor closed the door behind them and returned to his study, where he speedily immersed himself in a work on immunology. Maybe the Hunter's people knew what to do about antibodies, but there were other tricks to the medical trade.
It was not quite suppertime, and Bob and the Hunter made their way to the creek, where the boys should be. A sound of sawing gave evidence well before Bob was close enough to see that they were there; but work stopped as he came in sight.
"Where have you been? You've certainly ducked out of a lot of work this afternoon. Look at the boat!"
Bob looked. There was very little boat to see, as a matter of fact, for the removal of the bad timber had accounted for a remarkable percentage of the total, and very little replacement had as yet been accomplished. There was a reason for this, Bob noticed: there was very little replacement material on hand.
"Where's the stuff we picked out last night?" he asked Hay.
"A good question," said the other dryly. "Some of it was where we put it, and that's right here now. The rest had disappeared. I don't know whether the young kids cleaned it out or the men found it and used it. We didn't stay to get more; we thought we'd better get what was left down here and use it before it disappeared too. Well have to go back for more-there isn't nearly enough here to finish."
"You're telling me," said Bob, looking at the rather forlorn framework lying on the beach before them. Its state reminded him of something else, and he turned to Rice.