Of the functions of the lungs he was equally igno rant. He ascribed animal temperature to an ettcpulmo v-ug, a native fire residing in the left ventricle of the heart; and supposed that air was inspired to moderate its heat, and refrigerate the system : and that this air and mois ture were applied by the two appendages belonging to the heart, which, in compliance with his language, are still called auricles, and to which he assigned the office of bellows.
His ideas of digestion were not more correct. He believed that the stomach is a mere reservoir ; that the food was prepared by putrescence or concoction ; and was altogether ignorant of the channels by which it is afterwards conveyed through the system. He knew, however, the seat of the bile ; the secretion of urine in the kidnies ; and two Nessels by ,shkh he imagined that at least a part was conveyed to the bladder.
His anima, or vital principle, appears to be the same with the Ef.49V7ov 'rue, amid is in the left cavity of the heart. In all cases, even in thinking, it acts from necessity, and conducts the whole business of the sys tem by means of subordinate agents, which are called C44GettE lc, 'acuities, or powers. These c;uval.tfic are parts of the anima itself, and reside in the difkrent organs of the body, performing the functions of seeing, hearing, tasting, touching, and all the functions of the various organs. As these ;`avaaaia, however, are parts of the anima, ancl subject to its control, so the anima itself is only a portion of (1)ucrs, or nature, to which also it is subordinate. This ePauas is etherial fire, immortal, intel ligent, and just ; it hears and set s ; is acquainted with v, hat is present and future ; is sufficient for all things ; and perceives, untaught, whatever is necessaiy, and when it should be performed.
From this sketch of the anatomy and physiology of Hippocrates, our readers may perhaps be disposed to form a low estimate of his industry and talents. From his acknowledgment to I)emocritus, however, it appears that his opportunities of actual dissection were few ; and it is but justice to say, that wherever he has directed the whole force of his mind, he has far surpassed all his contemporaries; and that, in many parts of his works, he displays an enthusiasm for knowledge, an unwearied spirit of investigation, a clearness of discernment, a depth of reflection, an extent and quickness of compre hension, and a talent for accurate observation, which would have exalted him to eminence in any age ; and which entitled him justly to the fame which he has ac quired as the Father of Physic, and as one of the most illustrious characters who have done honour to science and mankind.
Till the time of Hippocrates, physic was considered as a subordinate branch of philosophy. lie was the first who exalted it to the rank of a distinct science, and made it the object of a separate profession. We may infer. therefore, that all prior philosophers must have been more or less acquainted with the animal economy. In the writings of many of them we find traces of their anatomical knowledge ; but our limits oblige us to con fine our attention to those who have, either by direct discovery, or by valuable hints, enlarged the boundaries of this science, or given extended views of its utility.
Among these, Socrates, the celebrated Athenian mo ralist, holds a distinguished rank. This illustrious sage was the first who perceived the use of anatomy in es tablishing the principles of natural theology ; and who demonstrated, from the form and situation of the dif ferent organs, the benevolence and foresight of the great Author of nature.
Plato, the friend and pupil of Socrates, likewise de voted a portion of his time to the study of the animal structure. The luxuriance of his imagination, however, and his fondness for theory, rendered him incapable of the cool and persevering investigation which physical subjects require. We shall search in vain, in the wri tings of Plato, for any minute or accurate description of particular organs; and if, in attempting to explain their functions, he sometimes approach the truth. we must ascribe this rather to fortunate conjecture than to pa tient and is e.l lir, Led inquiry. According to him, the brain is a prgiduetion ol the spinal marrow, Nvhich he believed to be the first organized part of the embryo, and the bond of union between soul and body idea which certainly bears some resemblance to the truth. He entertained some remarkable ideas concerning the heart, which he supposed the source of the veins, and the fountain from which the blood is briskly circulated through all the members. In a passage which Longinus quotes, as an instance of the sublime, he calls the 1,104x1 the pasture of the flesh; and adds, that the body is opened into a number of rivulets. like a garden inter sected with canals; that front these rivulets the veins receive their supply of vital moisture, and convey it, through various sluices, to the remotest parts of the system. This remarkable passage has induced many to believe, that Plato NVaS aCquainted with the circula tion of the blood. lie ne‘er once dreamt, however, that the rivulets returned to their source, but merely ima gined, that they conveyed the blood through the body as streams are diffused through a garden or meadow. So far from thinking of ally canals to bring back this fluid to the heart, he fancied that the arteries were mere air-vessels: an opinion which led hint, with limpedoc les, to confound the function of respiration with perspira tion; and to suppose, that the pores of the skin, as well as the lungs, were organs of breathing. As his philo sophy excluded a vacuum, he believed that the air which issues from the lungs, and through the pores of the skin, gave an impulse to the air which surrounds the body ; and that this ambient air, entering the lungs, re turned by the pores, or, entering the pores, returned by the lungs, in the course ol a semicircle. Ilis reasoning-, and mode of expression, betray a total ignorance of the functions of the heart, the lungs, and the skin. Ile ap pears to have been the first who attempted to account for the colour of the blood, which he imputes to the ac tion of fire residing in the heart.