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The blood in the middle sinus of the heart is the most attenuated.
He refers to the erroneous opinions of earlier writers, particularly to those of Syennesis of Cyprus, Diogenes Apolloniata, and Polybius, in regard to the origin and distribution of the blood-vessels; and after alluding to the difficulty of the investigation, proceeds to give his own account of them. These vessels, he declares, have not their origin in the head or brain; but are derived directly from the heart. Here the nerves also receive their origin. There are, he adds, two veins within the chest near the spine, the larger of which lies in front of the other, and more towards the right side. The smaller of the two is of a nervous structure when seen in the dead subject, and is called the aorta. Both of these vessels have their origin in the heart; through whatever viscera they pass, their course is continuous and uninterrupted. The heart constitutes, as it were, a part of them; particularly its anterior portion, where it is connected with veins passing both upwards and downwards; the heart itself resting in the midst. He attempts to show a connection between the branches of the vena-magna after passing through the diaphragm to the liver, with other veins passing upward towards the right axilla and arm; adding that the physicians, by drawing blood from the vessels of this arm, are enabled to cure certain diseases of the liver. A similar connection he elsewhere traces between the vessels of the spleen and those of the left arm.
The blood is thicker and darker in the lower,
than in the upper parts of the body. In the veins of all animals it is observed to palpitate. It is the only one of all the humors which is always present so long as life endures. It is supplied from the blandest fluids of the body, and formed within the heart. Deprived of it to a slight degree, the animal faints; to a greater extent, the animal dies. It changes in quality with the periods of life; and if too thin, it leads to diseases. When vitiated it gives rise to hæmorrhoidal flux, to epistaxis, to piles; and to varices. Pus is the result of its putrefaction. The bones, deprived of their fibrous envelope, desiccate; the bladder and other membranous or nervous sacks and tissues, when cut, never heal.
Among quadrupeds the hog is subject to three diseases, all of which he describes, giving the symptoms and mode of treatment, namely, - angina, which extends from the throat to the lungs and other parts of the body; scrofula, affecting the head and contiguous parts; and a disease of the bowels, which is usually fatal. Dogs are also subject to three diseases, rabies, angina, and podagra; all of which are briefly described. Rabies renders the animal insane, and all others that are bitten: by him, excepting man; and is fatal to all that are affected with it. And thus he treats on the diseases of other animals, savage and domestic.
From the foregoing exposition it will be seen that in his acquaintance with anatomy, physiology, and, we may also add, general pathology, Aristotle was far in advance of his epoch, approaching more closely to the medical science of modern times than
to the humoralism of antiquity. With him the blood was the pabulum vitæ, which, when disordered, gave rise to disease throughout the body. He has nothing to say either of the four elements, or of the four primitive humors; and in his study of minute distinctions, the characteristic trait of his writings on natural history as well as on every other branch of knowledge,-his doctrines were less in conformity with those of Hippocrates, than with those of the school of Cnidos.
The spirit of medical inquiry, as now shown, had already far outgrown the confines of the temples, Yet, as institutions of religion, most of these still maintained their ancient ceremonies. The Asclepion of Cnidos is known to have continued up to the age of Constantine; when, in common with other remaining abodes of pagan worship, by an edict of this emperor, it was leveled to the ground. But the Asclepiadæ of Cos, forgetting the influence of their former mysteries, were preparing the way for. a new order of institutions. By slow degrees they lost the suffrages of the multitude. Their sacred groves and fountains, no longer the resort of a confiding people, lay neglected and forsaken, by priests as well as patients; and at length the Roman Prefect, Turullius, in the days of Mark Anthony, while at Cos, regardless of the divinity that once had ruled within the precincts of its hallowed shades, ordered the groves to be destroyed, and the timber to be converted to the uses of the navy.* "Ac
Littré, loco citat. p. 11, from Lactantius. Schulze, p. 130.
minus credunt, quæ ad salutem suam pertinent, si intelligunt.**
But, notwithstanding the waning of the Asclepiada, the teaching of medicine continued to flourish. As early as the time of Aristotle, the profession had not only lost much of its ancient association with the priesthood, but had already become, divided into classes, the apothecaries, whose only business consisted in preparing and dispensing medicines; the physicians, engaged in general practice; and the medical philosophers, who pursued the study as a liberal science only, without devoting their attention to it as an industrial occupa tion. From this latter class were probably drawn the first teachers of the Alexandrian school; the opening of which, about three-fourths of a century. after the death of Hippocrates, marks the second great epoch in the progress of medical knowledge.
* Pliny, Hist. Nat,, lib. xxix. c. viii.
+ Aristotle, Politics, book iii. c. xi. and book iii. c. xvi. Aristotle himself, if we may believe Athenæus (Deipnosophists, book viii. c. 50), was in early life, after wasting his patrimony, the keeper of an apothecary shop in Athens.
PERGAMUS AND ALEXANDRIA.
THE rapid extension of Grecian arms under Alexander the Great, led to the diffusion of taste and learning among the surrounding nations. Pergamus and the new capital of Egypt, became points of scientific attraction, second only to Athens; and with the spread of general knowledge, the study of medicine extended to these cities.
At Pergamus, a library of immense extent had been accumulated by the predecessors of the first Attalus. The Asclepion of this city was among the earliest off-shoots from that of Epidaurus. The peristyle of the temple, and the avenues leading to it, were occupied as places of public instruction and scientific intercourse. Here the orators, sophists, and philosophers of the city, held their daily conferences, and sometimes, amused themselves in expounding to the sick the vaticinations of the priests. As a school of medicine, the Asclepión of Pergamus enjoyed a long-continued, celebrity; but its brightest era was after the first decadence of the Alexandrian school.
The city of Alexandria, from which issued much
* Vitruvius, lib. vii., præfatio, § 4.
† Le Clerc, lib. i. chap. xx., after Pausanias.