In his book Influence, Dr. Cialdini writes of a study at three Midwestern hospitals in which twenty-two separate nurses’ stations were contacted by a caller who claimed to be a hospital physician, and given instructions for administering a prescription drug to a patient on the ward. The nurses who received these instructions did not know the caller. They did not even know whether he was really a doctor (he was not). They received the instructions for the prescription by telephone, which was a violation of hospital policy. The drug they were told to administer was not authorized for use on the wards, and the dosage they were told to administer was twice the maximum daily dosage, and thus could have endangered the life of the patient. Yet in 95 percent of the cases, Cialdini reported, "the nurse proceeded to obtain the necessary dosage from the ward medicine cabinet and was on her way to administer it to the patient" before being intercepted by an observer and told of the experiment.