examination and then replaced, it immediately rejoined the main body without any trace of the earlier incision. This was fortunate since it enabled them to go through the meninges without having to worry about controlling fluid losses, and they could move laterally with minimal resistance and loss of time between the brain surface and the meningeal layer to the first objective, a deep fissure between two convolutions in the area suspected of housing the Groalterri telepathic faculty.
“Before we proceed,” Conway said, “is the patient aware of any unusual physical sensations or psychological effects?”
“No,” Hellishomar said.
For a few moments the main screen gave glimpses of Con-way’s hands and Seldal’s beak, brightly lit by the helmet lamp, as they pushed themselves carefully through the clear jelly between the smooth inner meninges and the massively wrinkled outer surface of the cortex and into the narrow crevice.
“As closely as we can estimate,” Conway went on, “this fissure extends about twenty yards on each side of our entry point and the average depth is three yards. On the upper brain surface the division between adjoining convolutions is clearly evident, but with depth the walls begin to press together. The pressure is not sufficient to be life-threatening, and the effort required to push the surfaces apart is minimal and does not reduce our mobility, but it would seriously hamper any surgical procedure that may become necessary and quickly cause disabling levels of fatigue. Soon we will have to deploy the rings.”
Hellishomar had not spoken directly to Lioren, even on the open channel, so that he had no way of knowing what was going through the patient’s mind. But Prilicla’s gauzy wings were beating slowly, and the stability of its hovering flight made it plain that there was no source of unpleasant emotional radiation in the area.
“Ease your mind, friend Lioren,” the empath said quietly. “At this time your anxiety is greater than friend Hellishomar’s.”
Greatly reassured, Lioren returned his attention on the main screen.
“This is the lobe where the highest concentration of trace metals occurs,” Conway said. “It has been chosen because similar traces have been associated with the telepathic function of the few other species known to possess the faculty, and although the operating mechanism remains unclear, the higher concentration of metal indicates the presence of an organic transmitter-receiver. It is the possible impairment of the patient’s higher brain functions, including the telepathic faculty, that we are trying to investigate and correct.
“Regrettably our charting of this area is imprecise,” it continued. “This is because the volume and density of the cranial contents would make it necessary to use very high power levels on our deep scanners, which would cause interference with neural activity.
“For this reason the portable, low-powered scanner will be used briefly and only in an emergency.
“The patient’s earlier cooperation in making voluntary muscle movements at our direction and submitting to external touch, pressure, and temperature stimuli has enabled us, by observing the local increases in neural activity, to identify those areas and eliminate them from the investigation. This information was obtained by sensor only, a detection system which produces no troublesome radiation, but which lacks the precision of the scanner.”
Lioren could not believe that there was anyone in the hospital, either presently on the staff or future trainees, who did not know the difference between a scanner and a sensor, and assumed that the explanation was for the patient’s benefit.
“It was expected,” Conway went on, “that the brain of a macro life-form would be more open and coarse- structured to correspond with its large body mass. As we can now see, the blood supply network is on the expected large scale, but the neural structure appears to be as highly condensed and finely structured as that of a being of smaller mass. I cannot … it is completely beyond rny ability to estimate the level of mentation possible to a brain of this size and complexity.”
Lioren stared at the enlarged image of Conway’s hands as they stretched slowly forward, pushed palms outward to each side, and then moved back out of sight, as if the Diagnostician was swimming endlessly through a fleshy ocean. For a moment he tried to put himself in Hellishomar’s place, but the thought of a white, slippery, two-headed insect crawling about in his brain was so repulsive that he had to control a sudden feeling of nausea.
Conway’s voice became uneven and its respiration more audible as it went on. “While we cannot be completely certain of what is or is not normal in this situation, it seems that the investigation so far has uncovered no evidence of structural abnormality or dysfunction. Our progress is being gradually impeded by increasing pressure from the fissure walls. At first this was ascribed to increasing fatigue in my arm muscles, but Seldal, who has no arms to tire, notes a similar increase in pressure against the outer surface of its carrying pouch. It is not thought to be a psychosomatic effect caused by claustrophobia.
“Mobility and the field of view are seriously reduced,” it added. “We are deploying the rings.”
Lioren watched as Conway struggled to pull the first ring over their heads and, with the help of Seldal’s incredibly flexible neck and beak, position it at waist level before breaking the compressed-air seal and inflating it around them. Two more rings were inflated at knee and shoulder level and joined into a hollow, rigid cylinder by longitudinal spacers. When the initial triple-ring deployment was complete, they added another ring and spacers to extend the structure forward. By deflating and withdrawing the rearmost ring and attaching it in front, and varying the lengths of the spacers, they were able to move the hollow cylinder and travel within it in any required direction. The open structure provided all-around visibility and ready access to perform surgery.
They were no longer swimmers in a near-solid ocean, Lioren thought, but miners boring through a tunnel that they carried with them.
“We are encountering increasing resistance and pressure from one wall of the fissure,” Conway said. “The tissues on that side appear to be both stretched and compressed. You can see there, and over there, where the blood supply has been interrupted. Some of the vessels are distended where the blood has pooled and others deflated and all but empty. This does not appear to be a naturally occurring condition, and the absence of necrosis in the area suggests that the circulation is seriously impeded but so far not completely blocked. The structural adaptation that has taken place also suggests that the condition has been present for a long time.
“Scanning is needed to find its cause and source,” Conway went on. “I will use the hand scanner briefly, at minimum penetration, now. How does the patient feel?”
“Fascinated,” Hellishomar said.
The Earth-human barked softly. “No emotional or cerebral effects are reported by the patient. I will try again with a little more penetration.”
For a few seconds Conway’s scanner image appeared on the main screen, then dissolved. The recording was projected onto an adjacent screen and frozen for study.
“The scanner shows the presence of another membrane at a depth of approximately seven inches,” the Diagnostician continued. “It is no more than half an inch thick, and has a dense, fibrous structure and a degree of convex curvature which, if continued uniformly, would enclose a spherical body of approximately ten feet in diameter. The underlying tissue structure is still unclear but shows a marked difference to that encountered so far. It may be that this is the site of the lobe responsible for the telepathic faculty. But there are other possibilities which can only be eliminated by surgical investigation and tissue analysis. Doctor Seldal will make the incision and obtain tissue samples while I control the bleeding.”
The main screen was filled with a picture of Conway’s hands, looking enormous and distorted because of the proximity of the helmet’s vision pickup, as they fitted a cutter to the Nallajim Senior’s beak. Then an index finger moved forward to outline the position and extent of the required incision.
There was a sudden blur of motion as the back of Seldal’s head and neck briefly obscured the operative field.
“You can see that the initial incision has not uncovered the membrane,” Conway went on, “but the underlying pressure has forced apart the edges of the wound to a degree that, if we don’t relieve the situation by extending the incision at once, there is a serious risk of it tearing open at each end. Seldal, would you go a little deeper and extend … Oh, damn!”
It was as Conway had foreseen. The incision had torn apart at each end and weightless globules of blood were drifting out of it and totally obscuring the operative field. Seldal had discarded the cutter because its beak came into view gripping the suction unit, which it moved expertly along and inside the wound so that Conway could find and seal off the bleeders. Within a very few minutes the wound, now with torn, uneven edges and fully three times its original length, was clear and gaping open to reveal at its base a long, narrow ellipse of utter
