Euge knew his status, had given it little thought for years. It was his private social contract, the working agreement by which the powers that be gave him the priceless opportunity to do research, in return for the--to him--worthless byproducts of same. Now, he thought as he went up in the elevator, the Dictator would be impatient--or at least eager--to hear the results of the newest experiments. The first tests of the new strain showed promise, by inoculations of a monkey, _Macacus rhesus_. The last series of experimental animals had belonged to another primate species. _Homo sapiens._ That was the crucial proof, whether men infected with Virus RM4-2197--R for rubeola, or measles, M4 for fourth-stage mutant, the rest the classification number of the culture--would die swiftly, surely, with a minimum of fuss. That was routine, too, but the results were not. The results had kept Euge lying awake for some nights now. Awake, open-eyed, face to face with himself as he had not been within his memory. He turned briskly into the contagion laboratory, deliberately making delay, explaining to himself that it would be best to have all the data on the new culture at his fingertips. The big room was a jungle of sealed glass cases where beady-eyed mice tumbled over each other, where healthy rabbits nibbled lettuce cheek by jowl with rabbits whose bodies seethed with mutant microbes. At the most crowded end of the room was Novik, brightest of the skilled young men assigned as assistants and apprentices to the great Dr. Euge, busy now with pencil and notebook, counting dead mice. * * * * * Euge looked over Novik's shoulder at the tallies. They were many. He asked, "What does it come to?" "So far," said Novik, "I've only been over the direct and remote cages. But--" he gestured at the remaining glass compartments on his right, "I'd be willing to bet the results of the delayed exposures are the same. Contagion, one hundred per cent; mortality, one hundred per cent. The only difference is, that where infected and healthy mice have a screen between them, the healthy ones get it slower--a few cases at first, then it runs right through them." "Mmm," said Euge without enthusiasm. The figures proved nothing new--only that the mutant virus bred true; for that matter, the 100-100 ratio of infections and deaths to exposures had been achieved already with RM3. Euge turned toward a double tier of cages along the side wall. These were small, built to contain one animal apiece, ten above, ten below. They were segregation cages; the lower tier was wired to a wall plug through a transformer and a mildly remarkable device, consisting of two slowly revolving, eccentric wheels and a relay, which insured that the metal floor of the ten cages should be slightly electrified at irregular intervals.