William Harvey — "The heart is the sun of the microcosm."

"The heart of animals is the foundation of their life, the sovereign of everything within them, the sun of their microcosm, that upon which all growth depends, from which all power proceeds."

"Nature is nowhere accustomed to exhibit herself more openly than in her failures."

"There is no perfect knowledge which can be entitled ours, that is innate; none but what has been obtained from experience, or derived in some way from our senses."

"All animals, even man himself, are produced from an egg."

"There is no science which does not spring from pre-existing knowledge, and no certain and definite idea which has not derived its origin from the senses."