"Sterile like germ-free," I said. "Gnotobiotic. I grew up in the Big Tank at Central University." * * * * * "You'll spend the night in the big tank at South Bend if you're snowing me, Sonny," he said. "Let's see your driver's license." I got my billfold out of the glove-compartment--a chastity-suit doesn't have any pockets--and handed my license to Bjornson. "John Bogardus, M.D.," he read. "You're a doctor, eh? This says you live at BICUSPID, Central University, South Bend. What's that BICUSPID, Doc? Means your practice is limited to certain teeth?" "I'm a resident in pathology, and I'm damned near out of air," I said, annoyed at the prospect of suffocating while acting straight-man to a state cop. "BICUSPID is the acronym for Bacteriological Institute, Central University Special Projects in Infectious Disease. I'm a Lapin, which is a human guinea-pig. I'm sorry, officer, that I broke the Indiana speed-limit but my air-filter is clogged with condensation. If I don't get back to the Big Tank at the University within the next few minutes, I'll run out of air. And you'll have to spend the rest of the evening testifying before St. Joseph's County Coroner." "So what happens if you crack open your space-helmet and breathe the air us peons use?" he asked. "Pretty quick, I'd die," I said. "I've got no antibodies, no physiological mechanism to combat inspired or ingested bacteria." "That's the sort of answer that makes my job the joy it is," Bjornson said. "Next thing you know, I'll be chasing drunken drivers from Mars." "There's no intelligent native life on Mars," I said. "You think maybe there are intelligent natives on U.S. Twenty?" he asked, returning my license. "Okay, Doctor Bogardus, I've bought your story. You leadfoot your bomb along after me, and we'll hit the Central campus like we're crossing the payoff line at the Mille Miglia." Bjornson cowboyed into the saddle of his bike, spurred it off and cut siren-screaming down the concrete toward South Bend and Central U. I jumped back into my sports-car and tailed him, the wind soaring past my 'phones like rocket exhaust. We cut through the field of Sunday drivers in a horizontal power-dive. I was half-blinded by the sweat condensed on my air-cooled face-plate. Formaldehyde bath or no, I'd have to cut in my reserve-air pretty soon. * * * * *