gristle

When you're chewing on life's gristle

Don't grumble, give a whistle

And this'll help things turn out for the best...

And it is a hard and cruel thing thus in early youth to taste beforehand the pangs which should be reserved for the stout time of manhood, when the gristle has become bone, and we stand up and fight out our lives, as a thing tried before and foreseen; for then we are veterans used to sieges and battles, and not green recruits, recoiling at the first shock of the encounter.