There are, in effect, two things, to know and to believe one knows; to know is science; to believe one knows is ignorance.

When doing everything according to indications, although things may not turn out agreeably to indication, we should not change to another while the original appearances remain.

Men ought to know that from the brain, and from the brain only, arise our pleasures, joy, laughter and jests, as well as our sorrows, pains, griefs, and tears.

Medicine is of all the Arts the most noble; but, owing to the ignorance of those who practice it, and of those who, inconsiderately, form a judgment of them, it is at present behind all the arts.

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

Many admire, few know.

There is one common flow, one common breathing, all things are in sympathy.