The second shift of workers that day was arriving at the aquariums. In the great pontooned building, vast rows of transparent plastic tubes, three feet in diameter, webbed back and forth among the tetron pumps. Vibrator nets cut the tubes into twenty-foot compartments. Catwalks strung the six-story structure, all flooded with deep red light that came from the phosphor-rods that stuck up from the pumps. Light toward the blue end of the spectrum disturbed the fish, who had to be visible at all times, to be moved, or to be checked for any sickness or deformity. In their transparent tubes, the fish floated in a state near suspended animation, vibrated gently, were kept at a constant 82°, were fed, were fattened, were sorted according to age, size, and species; then slaughtered. The second shift of workers moved into the aquarium, relieving the first shift. They had been on about two hours when a sweating hulk of a man who was an assistant feeder reported to the infirmary, complaining of general grogginess. Heat prostration was an occasional complaint in the aquarium. The doctor told him to lie down for a little while. Five minutes later he went into violent cramps. Perhaps the proper attention would have been paid to him had not a few minutes later a woman fallen from a catwalk at the top of the aquarium and broken one of the plastic arteries and her skull, six stories below. In the red light the workers gathered around her broken body that lay at the end of a jagged plastic tube. In the spread water, dozens of fish, fat and ruddy-skinned, flapped their gills weakly. The woman's co-workers said she had complained of not feeling well, when suddenly she went into convulsions while crossing one of the catwalks. By the time the doctor got back to the infirmary, the assistant feeder had developed a raging fever, and the nurse reported him violently nauseated. Then he died. In the next two hours, out of the five thousand two hundred and eighty people who worked at the aquariums, three hundred and eighty-seven were taken with cramps and died in the next two hours, the only exception being an oddball physical culture enthusiast who always drank two quarts of milk for lunch; he lasted long enough to be gotten onto the shuttle and back to General Medical on Toron, where he died six minutes after admittance, one hour and seventeen minutes after the onset of the cramps. That was the first case that General Medical actually received. It was not until the sixteenth case that the final diagnosis of barbitide poisoning was arrived at. Then someone remembered the query that had come in by phone from the military ministry that morning about the antidote.