CHAP. 89.—THE ARTERIES; THE VEINS: ANIMALS WITHOUT ARTERIES OR VEINS. THE BLOOD AND THE SWEAT.
The arteries are destitute of sensation, for they are devoid of blood. They do not, all of them, however, contain the vital spirit, and when one of them has been cut, it is only that part of the body that is reduced to a torpid state. Birds have neither veins nor arteries, which is the case also with serpents, tortoises, and lizards; and they have but a very small proportion of blood. The veins, which are dispersed beneath the whole skin in filaments of extreme thinness, terminate with such remarkable fineness, that the blood is able to penetrate no further, or, indeed, anything else, except an extremely subtle humour which oozes forth from the skin in innumerable small drops, and is known to us as “sweat.” The knot, and place of union of the veins, is the navel.
CHAP. 90. (38.)—ANIMALS, THE BLOOD OF WHICH COAGULATES WITH THE GREATEST RAPIDITY: OTHER ANIMALS, THE BLOOD OF WHICH DOES NOT COAGULATE. ANIMALS WHICH HAVE THE THICKEST BLOOD: THOSE THE BLOOD OF WHICH IS THE THINNEST: ANIMALS WHICH HAVE NO BLOOD.
Those animals in which the blood is more abundant and of an unctuous nature, are irascible; it is darker in males than in females, and in the young than in the aged: the blood of the lower extremities is the thickest. There is great vitality, too, in the blood, and when it is discharged from the body, it carries the life with it: it is not sensible, however, of touch. Those animals in which the blood is the thickest are the most courageous, and those in which it is the thinnest the most intelligent; while those, again, which have little or no blood are the most timorous of all. The blood of the bull coagulates and hardens the most speedily of all, and hence it is so particularly deadly[313] when drunk. On the other hand, the blood of the wild boar, the stag, the roe-buck, and oxen of all kinds, does not coagulate. Blood is of the richest quality in the ass, and the poorest in man. Those animals which have more than four feet have no blood. In animals which are very fat, the blood is less abundant than in others, being soaked up by the fat. Man is the only creature from which the blood flows at the nostrils; some persons bleed at one nostril only, some at both, while others again void blood by the lower[314] parts. Many persons discharge blood from the mouth at stated periods, such, for instance, as Macrinus Viscus, lately, a man of prætorian dignity, and Volusius Saturninus,[315] the Prefect of the City, who every year did the same, and yet lived to beyond ninety. The blood is the only substance in the body that is sensible of any temporary increase, for a larger quantity will come from the victims if they happen to have drunk just before they are sacrificed.