Pain is a sensation produced by something contrary to the course of nature and this sensation is set up by one of two circumstances: either a very sudden change of the temperament (or the bad effect of a contrary temperament) or a solution of continuity.

The physical signs of measles are nearly the same as those of smallpox, but nausea and inflammation is more severe, though the pains in the back are less.

As to the mental essence, we find it in infants devoid of every mental form.

Leeches should be kept a day before applying them. They should be squeezed to make them eject the contents of their stomachs.

There are no incurable diseases — only the lack of will. There are no worthless herbs — only the lack of knowledge.

God, the supreme being, is neither circumscribed by space, nor touched by time; he cannot be found in a particular direction, and his essence cannot change. The secret conversation is thus entirely spiritual; it is a direct encounter between God and the soul, abstracted from all material constraints.

Pure earth does not petrify, because the predominance of dryness over [i.e. in] the earth endows it not with coherence but rather with crumbliness. In general, stone is formed in two ways only (a) through the hardening of clay, and (b) by the congelation [of waters].