The physician must be able to tell the antecedents, know the present, and foretell the future — must mediate these things, and have two special objects in view with regard to disease, namely, to do good or to do no harm.

Life is short, art long, opportunity fleeting, experiment uncertain, and judgment difficult.

Each of the substances of a man's diet acts upon his body and changes it in some way and upon these changes his whole life depends.

For extreme illnesses extreme treatments are most fitting.

Rest as soon as there is pain.

Men ought to know that from the brain and from the brain only arise our pleasures, joys, laughter, and jests as well as our sorrows, pains, griefs and tears. ... It is the same thing which makes us mad or delirious, inspires us with dread and fear, whether by night or by day, brings us sleeplessness, inopportune mistakes, aimless anxieties, absent-mindedness and acts that are contrary to habit.

Men ought to know that from nothing else but the brain come joys, delights, laughter and sports, and sorrows, griefs, despondency, and lamentations. And by this, in an especial manner, we acquire wisdom and knowledge, and see and hear and know what are foul and what are fair, what are bad and what are good, what are sweet and what are unsavory…. And by the same organ we become mad and delirious, and fears and terrors assail us….All these things we endure from the brain when it is not healthy….In these ways I am of the opinion that the brain exercises the greatest power in the man.