A fat substance is incorruptible, but blood and all things
containing it corrupt rapidly, and this property characterizes
especially all parts connected with the bones. Blood is finest and
purest in man; and thickest and blackest in the bull and the ass, of
all vivipara. In the lower and the higher parts of the body blood is
thicker and blacker than in the central parts.

Blood beats or palpitates in the veins of all animals alike all
over their bodies, and blood is the only liquid that permeates the
entire frames of living animals, without exception and at all times,
as long as life lasts. Blood is developed first of all in the heart of
animals before the body is differentiated as a whole.