_The Views of Asclepiades with Regard to Physiology and Pathology._--The human body, according to the philosophy of Asclepiades, is composed of atoms--that is, small bodies which are invisible, have no definable quality, are in continual motion, through mutual pressure undergo modifications in form, and break up into innumerable smaller fragments or particles that differ both in size and in shape. The arrangement of these small bodies is such that intercommunicating spaces or pores are left between them, and through these channels flows a sap or juice containing larger and smaller particles; the larger ones composed of blood, and the smaller of vapor or heat. Health, according to Asclepiades, is that state in which the primitive atoms are properly distributed or placed and the flow of the juices in the pores takes place normally. When, however, the flow is arrested and the primitive atoms are disordered in their relations to each other and to the pores, or when the elements composing the fluid contents of the latter become mixed, disease results. Alterations in the pores themselves, as contradistinguished from the fluid contained within them, may also cause disease. Farther on, when the proper time arrives for considering the sect of the Methodists, I shall have occasion to discuss this subject again, and particularly that part of it which relates to pathology. In the meantime, however, I cannot resist the impulse to say a few words about the remarkable insight possessed by Asclepiades into the manner of construction of the human body, as manifested by this very brief but very significant anatomical and physiological description. Upon a first reading one might easily get the impression that Asclepiades has reference to only one kind or system of “pores” or channels--viz., such as serve for the circulation of tissue juices alone. But, upon a closer scrutiny of the text, one finds some warrant for suspecting that he had in mind more than one system of such channels; for he states distinctly that the fluid circulating in these pores contains larger particles composed of blood and smaller ones which consist of vapor (_spiritus_) or heat. The question suggests itself: Could a man who had no knowledge of Harvey’s discovery, who did not possess a microscope, and who at the same time believed--as did all the ancients--that air circulated in the arteries and blood in the veins, come any nearer to the actual truth than did Asclepiades? His description needs very few alterations and additions to make it fit correctly the system of terminal arterio-venous channels known to-day as arterioles and capillaries.