. . . it [masturbation] too often leads to grievous sin, even to that sin against nature, homosexuality. For, done in private, it evolves often into mutual masturbation - practiced with another person of the same sex - and thence into total homosexuality.
One might not think of light as a matter of fact, but I do. And it is, as I said, as plain and open and direct an art as you will ever find.