"But think," Ferris interjected, "what a boon it would be if everyone could be cured of headaches _forever_ by one simple injection." "I don't suppose the manufacturers of aspirin would like you. But it would please about everybody else." "Aspirins would still be used to reduce fever and relieve muscular pains," Mitchell said. "I see. Are you two saying you _have_ such a shot? Can you cure headaches?" "We think we can," Ferris said. "How can you have a specific for a number of different causes?" Macklin asked. "I know that much about the subject." "There _are_ a number of different causes for headaches--nervous strain, fatigue, physical diseases from kidney complaints to tumors, over-indulgence--but there is one _effect_ of all of this, the one real cause of headaches," Mitchell announced. "We have definitely established this for this first time," Ferris added. "That's fine," Macklin said, sucking on his pipe. "And this effect that produces headaches is?" "The pressure effect caused by pituitrin in the brain," Mitchell said eagerly. "That is, the constriction of blood vessels in the telencephalon section of the frontal lobes. It's caused by an over-production of the pituitary gland. We have artificially bred a virus that feeds on pituitrin." "That may mean the end of headaches, but I would think it would mean the end of the race as well," Macklin said. "In certain areas it is valuable to have a constriction of blood vessels." "The virus," Ferris explained, "can easily be localized and stabilized. A colony of virus in the brain cells will relax the cerebral vessels--and only the cerebral vessels--so that the cerebrospinal fluid doesn't create pressure in the cavities of the brain." The mathematician took the pipe out of his mouth. "If this really works, I could stop using that damned gynergen, couldn't I? The stuff makes me violently sick to my stomach. But it's better than the migraine. How should I go about removing my curse?" He reinserted the pipe. "I assure you, you can forget ergotamine tartrate," Ferris said. "Our discovery will work." * * * * * "Will work," Macklin said thoughtfully. "The operative word. It _hasn't_ worked then?" "Certainly it has," Ferris said. "On rats, on chimps...." "But not on humans?" Macklin asked. "Not yet," Mitchell admitted. "Well," Macklin said. "Well." He thumped pipe ashes out into his palm. "Certainly you can get volunteers. Convicts. Conscientious objectors from the Army." "We want you," Ferris told him. Macklin coughed. "I don't want to overestimate my value but the government wouldn't like it very well if I died in the middle of this project. My wife would like it even less." Ferris turned his back on the mathematician. Mitchell could see him mouthing the word _yellow_.