As the power of growth, nutrition, and generation operates all through
the entire body; and as it is by the blood that the body is nourished;
as the blood is contained in the veins; and as the veins, as well as
the blood, originate in the liver; this organ has been assigned as the
seat of that part of the soul called appetite; for appetite is involved
in the power of begetting, of feeding and increasing the body. Further
as the blood (purified by respiration) is subtle, light, mobile and
pure, the heart becomes a suitable instrument for the power of anger,
for the blood that possesses these qualities starts from the heart.
Therefore, with good reason, the heart is assigned as the seat of the
turbulent convulsions of the power of anger.