 What caused Macklin to lose his intelligence?
But Macklin is exactly what we need for a quick, dramatic test. "No, Harold, it isn't," Macklin admitted. "I would have said the common cold," Macklin replied, "but I suppose from what you have said you mean headaches." "What do you mean by that, Mrs. Macklin," Mitchell said sharply. "What could be wrong with Macklin?" he asked without removing his hand from the telephone. Jerry, their control in the experiment, who was practically Dean's twin except that he had received no injection of the E-M Virus, was stomping up and down punching his fingers through the wire, worrying the lock on the cage.
 His brain cells were not working properly
 He had suffered a stroke  His brain cells were not working properly  He was using heroin  He was only pretending