Needle

Do nothing that can harm your host! He needed food as well as oxygen. He could have consumed with relish and satisfaction any of the various forms of tissue surrounding him, but the law made selection necessary. There were certainly intruding organisms in this body-besides himself-and they were the logical food source, for by consuming them he would be eliminating their menace to his host and thereby helping to earn his keep. Identifying them would be easy; anything a leukocyte attacked would be legitimate prey for the Hunter. Probably the local microbes would not keep him fed for long, small as his needs were, and it would also be necessary to tap the digestive tract at some point; but that need not cause damage, unless a slightly increased appetite on the part of the host came under that heading.

For many hours the cautious exploration and adjustment continued. The Hunter felt his host awaken and resume activity, but he made no effort to look outside. He had one problem which must be carefully and accurately solved; and, although his dodging the attentions of thousands of leucocytes at once, as he had done for a time, may seem evidence to the contrary, his power of attention was limited. That had simply been an automatic action roughly comparable to a man's carrying on a conversation while he climbs stairs.

Filaments of the Hunter's flesh, far finer than human neurons, gradually formed an all-inclusive network ' throughout Bob's body from head to toe; and through those threads the Hunter came gradually to know the purpose and customary uses of every muscle, gland, and sense organ in that body. Throughout this period most of his mass remained in the abdominal cavity, and it was more than seventy-two hours after his first intrusion that he felt secure enough in his position to pay attention once more to outside affairs.

As he had done with the shark, he began to fill the spaces between the boy's retinal cells with his own body substance. He was actually able to make better use of Bob's eyes than their proper owner could, for the human eyes see in maximum detail only those objects whose images fall within an area of retina less than a millimeter across. The Hunter could use the whole area on which the lens focused with reasonable sharpness, which was decidedly larger. In consequence, he could examine with Bob's eyes objects at which the boy was not looking directly. This was likely to be a help, since many of the things in which the hidden watcher was most interested would be too commonplace to the human being to attract his direct gaze.

The Hunter could hear dimly even within the human body, but he found it helpful to establish direct physical contact with the bones of the middle ear. Thus, hearing as well as seeing better than his host, he felt ready to investigate the planet on which chance had marooned him and his quarry. There was no further reason-he thought- for delay in searching for and destroying the criminal of his own race now free on the world. He began to look and listen.

The search itself he had never regarded as more than a routine job. He had had similar problems before. He had expected to look around from the vantage point of Bob's body until he found the others, leave and eliminate his opponent by standard means-regardless of the fact that all his equipment was at the bottom of the sea. He had had, in short, a viewpoint which is excusable in a space navigator but not in a detective: he had been regarding a planet as a small object and thinking his search was practically over when he had narrowed it down to one world.

He was rudely jolted out of this attitude as he took his first look around since meeting Bob Ki

The flight lasted for several hours and had probably already consumed several. The Hunter quickly gave up the attempt to memorize landmarks over which they passed. One or two of them did stick in his mind and might give a clue to direction if he could ever identify them later; but he put little trust in this possibility. He must keep track of time rather than position, and when he was more familiar with human ways find out where his host had been at the time of his own intrusion.

The view itself, though, was interesting, even if the landmarks were lacking. It was a beautiful planet, from his alien viewpoint; mountains and plains, rivers and lakes, forests and prairies were all visible at various times, now clearly through miles of crystal atmosphere and now in glimpses between billowing clouds of water vapor. The machine he rode was also worthy of attention; from Robert's window he could not see very much of it, but that little told him a great deal. A portion of a metal wing was visible, bearing attachments which evidently contained engines, as rapidly rotating air foils were visible ahead of them. Since the craft was presumably symmetrical, the Hunter decided there must be at least four of these engines. He could not tell with accuracy how much of then- energy was wasted in heat and sound-for one thing, he suspected that the cabin in which he rode was quite effectively sound-proofed. The machine as a whole, however, suggested that this race had evidently attained a considerable degree of mechanical advancement, and a new idea blossomed from that: might he not attempt to enter into communication with this being which was his host and secure its active co-operation in his, search? It was a point well worth considering.

There was plenty of time for thought before the airplane gradually began to descend. The Hunter could not see directly ahead, and it happened that they entered a solid cloud layer almost immediately, so he was unable to get any idea of their destination until just before the landing. He chalked up another point for the race: they either had senses he lacked, or were very competent and ingenious instrument makers, for the descent through the clouds was as smooth as any other part of the flight.

After some time spent letting down through the gray murk, the machine broke out into clear air. As it banked into a wide turn the Hunter saw a large city built around a great, crowded harbor; then the faint drone of the engines increased in pitch, a large double wheel appeared below one of the nacelles, and the craft glided easily downward to contact with a faint jar a broad, hard-surfaced runway located on a point of land across the harbor from the largest buildings.

As Robert disembarked he glanced back at the airplane, so the Hunter was better able to form an estimate of its size and construction details. He had no idea of the power developed by the four bulky engines, and could not, therefore, guess at the speed; but he could see the quivering in the air above the huge nacelles that told of hot metal within and knew at least that they were not the phoenix converters used by his race and its allies. Whatever they were, though, it had already become evident that the machine could put a very respectable fraction of the planet's circumference behind it without having to descend for fuel.

After alighting from the airplane the boy went through the usual formalities incident to reclaiming his baggage, took a bus around the harbor to the city, walked about for a while, and visited a movie. This the Hunter also enjoyed; his vision persistence involved about the same tune lapse as the human eye, so he saw the show as a movie rather than a set of separate pictures. It was still daylight when they emerged and walked back to the bus station, where Bob reclaimed the luggage he had checked, then they boarded another bus.