On this occasion Conway was discussing e-t comparative physiology.
….. Unless you are attached to a multienvironment hospital like this one,” Conway was explaining to Lieutenants Haslam, Chen and Dodds, and with a brief glance at the vision pickup to include Captain Fletcher in Control, “you normally meet extraterrestrials one species at a time, and refer to them by their planet of origin. But here in the hospital and in the wrecked ships we will encounter, rapid and accurate identification of incoming patients and rescued survivors is vital, because all too often the casualties are in no fit condition to furnish physiological information about themselves. For this reason we have evolved a four-letter physiological classification system, which works like this:
“The first letter denotes the level of physical evolution,” he continued. “The second letter indicates the type and distribution of limbs and sensory equipment, which in turn gives us information regarding the positioning of the brain and the other major organs. The remaining two letters refer to the combination of metabolism and gravity and/or atmospheric-pressure requirements of the being, and these are tied in with the physical mass and the protective tegument, skin, fur, scales, osseous plating and so on represented by the relevant letter.
“It is at this point during the hospital lectures,” Conway said, smiling, “that we have to remind some of our e-t medical students that the initial letter of their classifications should not be allowed to give them feelings of inferiority, and that the level of physical evolution, which is, of course, an adaptation to their planetary environment, has no relation to the level of intelligence . .
Species with the prefix A, B or C, he went on to explain, were water-breathers. On most worlds, life had originated in the sea, and these beings had developed high intelligence without having to leave it. The letters D through F were warm-blooded oxygen-breathers, into which group fell most of the intelligent races in the Galaxy; and the G to K types were also warm-blooded but insectile. The L’s and M’s were light-gravity, winged beings.
Chlorine-breathing life-forms were contained in the 0 and P groups, and after that came the more exotic, the more highly evolved physically and the downright weird types. These included the ultra-high-temperature and frigid-blooded or crystalline beings, and entities capable of modifying their physical structures at will. Those possessing extrasensory powers sufficiently well developed to make ambulatory or manipulatory appendages unnecessary were given the prefix V, regardless of physical size or shape.
….. There are anomalies in the system,” Conway went on, “but these can be blamed on a lack of imagination by its originators. One of them was the AACP life-form, which has a vegetable metabolism. Normally, the prefix A denotes a water-breather, there being nothing lower in the system than the piscine life-forms. But then we discovered the AACPs, who were, without doubt, vegetable intelligences, and the plant came before the fish-”
“Control here. Sorry for the interruption, Doctor.”
“You have a question, Captain?” asked Conway.
“No, Doctor. Instructions. Lieutenants Haslam and Dodds to Control and Lieutenant Chen to the Power Room, at once. Casualty Deck, we have a distress call, physiological classification unknown. Please ensure maximum readiness-”
“We’re always ready,” said Naydrad, its fur bristling in irritation.
“Pathologist Murchison and Doctor Conway, come to Control as soon as convenient.”
As the three Monitor Corps officers disappeared rapidly up the ladder of the central well, Murchison said, “You realize, of course, that this means we will probably not be given the Captain’s second lecture on control-system organization and identification in vessels of non-bifurcate extraterrestrials this afternoon.” She laughed suddenly. “I am not an empath like Prilicla here, but I detect an overall feeling of relief.”
Naydrad made an untranslatable noise, which was possibly a subdued cheer in Kelgian.
“I also feel,” she went on, “that our Captain is merely being polite. He wants to see us up there as soon as possible.”
“Everybody,” said Prilicla as it began checking the e-t instrument packs, “wants to be an empath, friend Murchison.”
They arrived in Control slightly breathless after their climb up the gravity-free well past the five intervening decks. Murchison had considerably more breath available than Conway, even though she had used a lot of it telling him that he was running to adipose and that his center of gravity was beginning to drop below his waistline-something that had not happened to the delightfully topheavy pathologist over the years. As they straightened up, looking around the small, darkened compartment and at the intent faces lit only by indicator lights and displays, Captain Fletcher motioned them into the two supernumerary positions and waited for them to strap in before he spoke.