text: "You remember the problem of anaesthesia and cyoziworms?" asked Wulpmegarn as we walked down corridors in his citadel of medical power.
  
  "Anaesthetics kill worms. A dose strong enough to put me out would have killed my worm, and that would kill me," said Tarcuna.
  
  "Precisely. A troublesome problem, we thought. But of course it was a crucial clue. Worms are, in many cases, more strongly affected by many sorts of drugs, and neurodepressants in particular. So, we give our wormridden patients a moderate dose of, say, kikodanzan. Tarcuna may know it as 'bosum'."
  
  "I took a biology class from you! I'm not just a whore! I know what kikodanzan is." Tarcuna drew a chemical structure. "That, right?" I looked at it but didn't understand it. Once I'm married and deposed I need to learn the local science.
  
  Wulpmegarn erased one glyph, and added a diaresis to another. "Close, close. Spotty, Narararn, are you familiar with the drug?"
  
  Nrararn said, "The only hoven drug that does much for me is alcohol, and it takes a barrel of brandy before I feel it."
  
  "Well, bosum induces a satisfied indolence, or a pleasant torpor, or a heavy approximation of post-coital slumber, depending on the dosage and individual sensitivity. We use a small dose, which tends to make our patients lazy and contented... and leaves the worm in a pleasant torpor. Too torpid to make many demands on the patient in most cases."
  
  Tarcuna laughed. "We never got many bosum-guys when I was a whore. They're too lazy to want any sex. So I don't think much of your plan so far. What good are drugged-out, contented worms?"
  
  "Lleredh was furious at the treatment. He wants the worms to die in torment, not to pass their days in a pleasant torpor. Ythac had to defeat him in a terrible combat before he assented to let us use this treatment on any broad scale. It is not perfect! Some people are too susceptible to the drug, and have a choice between losing their will to the worm or to bosum. Some worms are too susceptable, and die, and kill the patient as well. Some are not susceptable enough. Bosum has long-term medical disadvantages for hovens and for worms. It shortens the worm's life expectancy from some twenty years to, we estimate, ten to twelve years. This of course curtails the patient's life too."
  
  "I'd rather have ten to twelve hours half-free of a worm than twenty years wormridden. Ten to twelve years is a good deal indeed!" said Tarcuna.
  
  "Our patients generally agree," said Wulpmegarn.
  
  "Really? You're too credulous, Wulpmegarn. How do you know it's not fully controlled hovens pretending to be partially uncontrolled?" I had to ask.
  
  I didn't understand his answer, which was full of science, so I interrogated a few patients. The interrogations went mostly like this, about three times, with variations:
  
  Me: "Are you wormridden?"
  
  Patient: [truthfully] "Yes."
  
  Me: "Is the worm controlling you now?"
  
  Patient: [truthfully] "Just a little."
  
  Me: "Would you like me to rip the worm out of you by sorcery and surgery?"
  
  Patient: [truthfully] "Why yes, thank you very much."
  
  "Well, I guess your drugs work," I admitted.
  
  "Indeed they do, Spotty. Indeed they do," said Wulpmegarn. "You have surely noted the thick orange plastic vests that our patients all wear?"
  
  "They are certainly thick, and orange, and plastic," I said. Which is to say that I had seen them but hadn't noticed that all the patients wore them.
  
  "Those vests provide a backup, a failsafe in case the drugs wear off too soon. They are too thick and too full of chainmail for the cyoziworm to penetrate. As long as the vest is on, the worm can neither feed nor colonize. Removing the vest without the key is a considerable challenge, and in any case the lock is unreachably in the center of the back. If it is tampered with, or if the patient does not return to the treatment center at a suitable time, the vest will set off a very loud alarm and broadcast a strong radio signal, and inject a personally-tailored dose of kikodanzan. And, incidentally, become rigid, hampering even a wormridden's movements. It even has four independent batteries, making it very challenging to disable its electrical systems."
  
  Tarcuna whistled. "Very nice." I stared at her. "Jyothky: a wormridden wearing that sort of suit is going to have a great deal of trouble hurting anyone else, or escaping. The Tresteans don't need to put them in cyozi-camps any more."
  
  Wulpmegarn nodded. "Camps are still needed. A minority of patients do not respond well to our current repertoire of drugs. But the camps can be less like prisons, and more like asylums. They can be near cities. Patients can visit their families several times a week. The guards carry tranquilizer darts, not twistor guns. Of course, full freedom is not possible on the current regimen. The worms must be permitted a day or two of wakefulness each week to feed — on farm animals that we provide, not on people. Goats. We are confident that cyoziworms cannot colonize goats."
  
  I couldn't think of anything more to add. "Oh — how do you even find the wormridden?"
  
  "Screening and testing. Everyone in Perstra has been screened, and will be screened every four years. Not by the barbaric and primitive process you saw years ago! We have more accurate blood and urine tests than we did. We use a device to measure skin conductivity on the udder, thereby detecting internal or external scarring. It is not as accurate as a careful shaving and visual inspection under a microscope, but it is not as humiliating or unpleasant afterwards, either. Anyone appearing potentially wormridden on even one of these tests is given a quarantine test. They are placed in one half of a divided chamber, and provided with all necessities and comforts. In the other half is a goat, also provided with all necessities and comforts. The room is under constant observation by mechanical and often hoven means. And then we wait. Should the subject enter the goat's half of the chamber and attempt to feed a cyoziworm upon the goat's blood, we know that he is infested. Should the subject suffer sudden anemia, ditto. Should a month go by without either of these, the subject is uninfested; in that time, the worm would have had to feed several times."
  
  "That sounds quite accurate," I said. Animals need to eat: I know that much science.
  
  "It is extremely accurate. We only missed a single worm in Perstra, and Ythac found that one by his magic. It is also a logistical infestation of salt-lice to administer. When we instituted it, we expected to run short of rooms, which we did, and recording equipment, which we also did. We even ran short of goats. We have an alternate second-line test, which we used for a while, abandoned due to a regrettably high death rate, and are refining and hope to reintroduce as a voluntary alternative in some months. Full-body intrascopy is too dangerous, too likely to injure the worm and poison the patient. However, a cerebral intrascopy merely looks at the worm's probes, not its soft body, and is much less likely to do any injury. If a narrow intrascope shows a dozen thorny probes, the patient is infested; if not, not. Of course, once in a while it does rend the worm and kill the patient. And of course intrascopy of even healthy people has health risks."
  
  Then he showed us the equipment. Tarcuna, who loves twistor beams and hadn't gotten to play with them at all since she had taught me how to breathe them (two years ago, now), had a wonderful time inspecting the intrascopy equipment. Nrararn and I got bored, turned into ducks, snuck off, and behaved in ways suitable to a married couple on the nearest pond. I don't mind amusing Nrararn. The scientists didn't much care if we understood their methods or not.
  
  Wulpmegarn was a proud, proud man. He deserved it. He and his scientists and technicians had started to vanquish a foe against which twenty-two dragons had made no particular progress. (That's too nice to us. We had a great deal of regress.) I did stay to do surgery on some hovens, just to prove that dragons aren't entirely helpless or useless. But Wulpmegarn picked my patients, not me, and he picked them for responding poorly to his methods.