3. Man has the thinnest and purest blood, that of the ox and ass is the
thickest and blackest of all viviparous animals. The blood is thicker
and blacker in the lower than in the upper part of animals. The blood
palpitates in the veins alike in all animals; this alone of all the
fluids exists in every part of the body of living subjects, and as long
only as they are alive. The blood first of all exists in the heart of
all animals before it is distributed through the body. When deprived of
their blood, or if the greater part escapes, they faint away; but when
a very great deal is lost, they die. When the blood becomes very much
liquefied, illness ensues, for it becomes like serum, and flows through
in such a manner, that some have perspired blood; and when taken out
of the body, it does not coagulate into a mass, but into separate and
divided portions.
4. In sleeping animals, the blood in the extremities is diminished, so
that it does not flow freely when they are pricked. Blood is formed
from serum, and fat from blood. When the blood becomes diseased,
hæmorrhoids are produced, either in the nose or anus, and a disease
called ixia.[96] When the blood becomes corrupted in the body, pus is
formed, and from pus a scab. The blood in females differs from that of
males, for it is more thick and black in females of similar health and
age. In the whole of the body the quantity of blood is less in females,
but internally they are more full of blood. Of all females, women have
the most blood, and the catamenia are more abundant in them than in
other females.
[96] Varicose veins.
5. When this blood is diseased, it is called a flooding. Women have a
less share in other diseases; but a few are afflicted with ixia, and
with hæmorrhoids and bleeding from the nose; when any of these take
place, the catamenia decrease. The blood differs in proportion to the
age in quantity and appearance, for when very young, it is more like
serum, and very abundant; in the aged it is thick, black, and in less
quantity; in those in the prime of life it is between these. In aged
persons the blood coagulates quickly in the body, or on the surface;
but in young persons this does not take place. Serum is imperfect
blood, because it has not ripened, or because it has become more fluid.
CHAPTER XV.