"Idiot." (Illustrated World Encyclopedia.)

I get the feeling this encyclopedia was written for teens, maybe. Anyway, it was published around 1970.

Idiot: An idiot is someone with so little intelligence that he is not able to take care of himself in the simplest ways. He is not able to feed or dress himself, and his mental ability never gets to be more than that of a two year old child. Idiocy may be caused by injuries to the brain, but most idiots have been that way since birth. There is not much that can be done to help these unfortunate people, except to place them in institutions where they can be cared for. According to law, an idiot cannot sign a contract or be blamed for a crime he commits.