Pope Pius XII
"Indeed, the danger of bad reading, under certain aspects, is more harmful than bad company because it is capable of rendering itself prodigiously more intimate. How many girls or young women, alone in their rooms with a popular little book, allow it to speak to them crudely about things they would never permit others even to whisper about in their presence, or allow it to describe scenes which they would not for anything in the world wish to enact either as participants or victims! Alas, they are but preparing themselves to do so tomorrow! Other Christian men and women, who from infancy have tried the righteous path, complain of the unexpected increase of temptations within them before which they feel progressively weaker.
"Perhaps, if they were to examine their conscience, sincerely, they would have to acknowledge they have read a sensuous novel, perused an immoral magazine, or looked at improper pictures! Poor souls, can they truly and logically complain that a flood of muck threatens to engulf them when they themselves opened the dikes of a poisonous ocean?.....
"'I am no longer a child,' says a young woman, 'and I know life; therefore, I have the desire and the right to know it even better.' But the poor thing does not realize that her language is the language of Eve, face to face with the forbidden fruit; and does she think perhaps that to know love and experience life it is necessary to examine all its abuses and deformities?
"In the same way, a young man says, 'I am no longer a child, and at my age sensuous descriptions no longer mean anything.' Is he sure of this? If true, this would be an indication of unconscious perversion resulting from reading already indulged in, like certain legends of Mithridates, King of Pontus, who grew, prepared and experimented with poisonous herbs to which he wished to become immune; hence, the word mithridatism."