The Art of Medicine

Disease, for example, is the primary cause of impaired function; a putrid humor is the cause of the disease; an obstruction is the cause of the putrefaction. To that same impaired function, putrefaction and obstruction are causes by accident and in a second place. In a like manner, the faculty of the liver is the efficient cause of blood; innate heat is the instrument, which indeed also has the rationale of an efficient cause, just as a carpenter is the efficient C cause of a house, but an axe is the instrument. Furthermore, regarding efficient causes, some constantly accompany the effect, such as those that are internal. Others can be absent, such as those which the Greeks call prokatarktikas preceding/procatarctic and we call evident and external; for instance, the heat of the Sun is the cause of a daily fever even if it has ceased from burning. Causes of this kind act either by the necessity of nature or by the will of the maker. From these internal efficient causes, which accompany the effect and act by necessity, whether they be alone or joined with other assisting causes, true differences are taken, as we shall explain more fully later. D We call that "matter" which receives forms, both that which comes to pass by the aid of nature and that which is made by art. That which receives natural forms is either simple and unmixed, or composite. Aristoteles Aristotle calls the simple one "primary" because, as I suppose, it receives the forms of the primary bodies, which are called elements.