Illustration and design for Kurt Vonnegut's collection of short stories "Welcome to the Monkey House".
In the short story "Welcome to the Monkey House" a drug is developed by a chemist to make zoo monkeys numb from the waist down. The pious chemist was determined to rid the monkeys of "inappropriate behavior" after taking his family to the zoo on Easter Sunday, and witnessing a monkey touching himself. Later, due to world over population, the drug was made mandatory for all humans as a form of "ethical" birth control. The main character of the story, Billy the Poet, and others who refuse to take the drug are referred to as "nothing heads".