The Book
The short story that the film is based on goes by the bizarre title of The System of Doctor Tarr and Professor Fether (referring to a severe form of humiliation meted out to people who deserved punishment - being brushed in hot tar and then coated with feathers). It is the original tale from which all other versions stem whereby the lunatics have taken over the asylum.
The tale is told in the first person by a gentleman who, while travelling in France, makes a visit to a private mad-house as he has heard great things about their methods of treatment. A friend introduces him to the superintendent, Monsieur Maillard, who welcomes him and invites him to dine with six other guests. The behaviour of the guests becomes increasingly eccentric, but the gentleman is uncertain whether it is the peculiarity of the Europeans (and doesn't want to make a social faux pas) or that he is dining with lunatics.
The end of their meal is interrupted when a group of freakish apes crash into the room and a fight ensues. The real guards and doctors of the asylum had been locked in the basement, tarred and feathered. One had escaped, released the others and they had now successfully recaptured the mad-house.