12. And since some nourishment must needs also be provided by nature for the element of heat—for it is not possible that the fire should last by itself, without being nourished by its proper food—therefore the channels of the blood, issuing from the liver as from a fountainhead, accompany the warm spirit everywhere in its way throughout the body, that the one may not by isolation from the other become a disease and destroy the constitution. Let this instruct those who go beyond the bounds of fairness, as they learn from nature that covetousness is a disease that breeds destruction.