letter: a written message addressed to a person or organization
document: anything serving as a representation of a person's thinking by means of symbolic marks
ketamine: a general anesthetic and tranquilizer (not a barbiturate) that is administered intravenously or intramuscularly; used mainly by veterinarians or for minor surgery with geriatric or pediatric patients; taken in large doses it causes hallucinations similar to those associated with the use of PCP