According to Hollywood lore, the black children were supposed to trip and fall running away from Boy Tarzan. When they did do it with enough comedy, the director strung up piano wire, leading to several of the child actors with lacerated shins, bleeding on set.
When Shirley Temple failed to perform, they sent her to a black box with nothing to sit on but a block of ice.
These are exactly the kind of savage and barbaric practices that need to be employed again in today's Hollywood. If Megan Fox had to suffer Solitary Ice Confinement every time she held up production maybe she wouldn't be such an insufferable dink.