And so I conclude that blood lives and is nourished of itself and in no way depends on any other part of the body as being prior to it or more excellent... So that from this we may perceive the causes not only of life in general... but also of longer or shorter life, of sleeping and waking, of skill, of strength and so forth.

The animal's heart is the basis of its life, its chief member, the sun of its microcosm; on the heart all its activity depends, from the heart all its liveliness and strength arise. Equally is the king the basis of his kingdoms, the sun of his microcosm, the heart of the state; from him all power arises and all grace stems.

Only by understanding the wisdom of natural foods and their effects on the body, shall we attain mastery of disease and pain, which shall enable us to relieve the burden of mankind.

It is, however, an argument of no weight to say that natural bodies are first generated or compounded out of those things into which they are at the last broken down or dissolved.

When in many dissections, carried out as opportunity offered upon living animals, I first addressed my mind to seeing how I could discover the function and offices of the heart's movement in animals through the use of my own eyes instead of through the books and writings of others, I kept finding the matter so truly hard and beset with difficulties that I all but thought, with Fracastoro, that the heart's movement had been understood by God alone.

Moderate labor of the body conduces to the preservation of health, and cares many initial diseases.

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.