Life is short, art is long, occasion sudden, experiment dangerous, judgment difficult.
Neither is it sufficient that the physician do his office, unless the patient and his attendants do their duty and external conditions are well ordered. In extreme diseases extreme and searching remedies are best. Old men easily endure fasting, middle-aged men not so well, young men still less easily, and children worst of all, especially those who are of a more lively spirit. Those bodies that grow have much natural heat, therefore they require good store of food or else the body consumes, but old men have little heat in them, therefore they require but little food, for muchnourishment extinguishes that heat. And this is the reason that old men do not have very acute fevers, because their bodies are cold.