To the Editor.— In a recent issue (229:763, 1974), Shaffer describes a series of cases characterized by anesthesia, analgesia, nystagmus, dizziness, diplopia, visual distortions, and psychosis. These findings were attributed to ketamine, a derivative of phencyclidine. Phencyclidine is a major component of street drug preparations.1In one series, phencyclidine was detected in 184 of 237 street...