CALLISTHENES, a pupil of Aristotle, was told, when his teacher sent him to Alexander, to observe a special mode of self-discipline. 1 He was to speak most agreeably, yet as seldom as possible, in the presence of one who held the power of life and death on the tip of his tongue. Writers who have carefully studied animals’ behaviour say that some, although irrational creatures, protect their lives by deep silence. These include geese, which, once they have migrated from eastern lands on account of the intense heat and are heading for the west or north, have to pass Taurus, 2 a mountain infested with eagles. Fearing these rapacious birds, the geese stop their beaks with pebbles as they fly past, in case they should be tempted to call out by force of habit or necessity and so risk danger through betraying their presence to the eagles. After they have flown beyond the summit and foothills of the mountain without a sound, they spit out the pebbles and, free now from restraint, emit loud, honking cries as they travel through the open spaces of the sky. Likewise, any person in a similar position whose fortune it is to be encumbered with a diplomatic mission or other such responsibility, should consider imitating the example of the geese and remain quiet, exercising a suitable caution about whom he speaks to. A word once uttered can never be called back, as the popular saying goes. It is therefore preferable to model oneself on the geese rather than Callisthenes. They have saved their lives by a brief reticence, while he lost his merely through allowing his tongue to wag a little too freely, for he had neither paid attention to the advice of his superb teacher, nor learnt the blessed quality of silence from Pythagoras. Remaining quiet at the right moment is more praiseworthy than delivering a timely speech.