(82) Timaeus: For seeing that there are four elements of which the body is compacted,—earth, fire, water and air,—when, contrary to nature, there occurs either an excess or a deficiency of these elements, or a transference thereof from their native region to an alien region; or again, seeing that fire and the rest have each more than one variety, every time that the body admits an inappropriate variety, then these and all similar occurrences bring about internal disorders and disease. For when any one element suffers a change of condition that is contrary to nature, all its particles that formerly were being cooled

(86) Timaeus: and it produces diarrhoea and dysentery and all suchlike maladies. When a body has become diseased mainly from an excess of fire, it produces constant inflammations and fevers; when from air, quotidian fevers; when from water, tertian fevers, because that element is more sluggish than air or fire; and when from earth, which is the fourth and most sluggish of the elements and is purged in four-fold periods of time, it causes quartan fevers and is cured with difficulty.

(122) "Thou art of fire; return to thy root!" In the body there are seventy-and-two diseases; Disease comes to rend the body asunder, The four elements are as birds tied together by the feet; Death, sickness and disease loose their feet asunder. The moment their feet are loosed from the others, 'The bird of each element flies off by itself. The repulsion of each of these principles and causes That it may dissolve these composite bodies of ours, The bird of each part tries to fly away to its origin;