Harry T. Chimpanzee was an alpha male research chimp whose blood was used to make an extract called transfer factor, given to patients to increase their immune response to M. leprae, the bacillus that causes Hansen's disease. Known officially as a special study case, he weighed about 160 pounds and was noted for extremely strong upper extremities, once nearly breaking out of a cage made of aluminum bars by brute strength alone. One Thursday night, he escaped from his locked cage on the third floor of the infirmary building even though the padlocked four-number combination lock faced away from him, opened outward, and the cage remained locked and intact. He apparently took the fire escape down, entered the hallway of the Ladies Infirmary, briefly encountered a nurse who knew him, then went into a blind patient's room and sat beside her bed to watch television, something he often did on the third floor. After alarms were raised and efforts began to obtain a tranquilizer gun from New Orleans Zoo personnel, word came that Harry had returned to the second floor of the infirmary, was heading for the men's wing, and had been killed with a shotgun for the safety of patients and station personnel. Dr. Robert Hastings later emphasized that Harry had been a much loved research subject who lived on the third floor of the hospital infirmary in the 1970s and did not want him remembered as dangerous.