Another prominent theory throughout the Hippocratic books is that of Fluxions, meaning thereby about what we would call congestions, or conditions which we would say were ordinarily caused by cold, though certain fluxions were supposed to be caused by heat, because the tissues thereby became rarefied, their pores enlarged, and their humor attenuated so that it flowed easily when compressed. The whole theorv of fluxion was founded on the densest ignorance of tissues and the laws of physics, the body of man being sometimes likened to a sponge and sometimes to a sieve. The treatment recommended was almost as crazy as the theory. Certain other theories have complicated or disfigured the Hippocratic writings, and certain have been founded on the consideration of two elements--i.e., fire and earth--or on the consideration of one single element which was supposed to be air,--the breath, or _pneuma_; and there was--lastly--the theory of any _excedent_, which is very vague; of all of these we may say that they are not of sufficient interest to demand expenditure of our time.
The eclat{ 027} which the second (i.e., the Great) Hippocrates gave to the school of Asclepiadæ in the Island of Cos long survived, and many members of his family followed in his footsteps. Among his most prominent successors were _Polybius, Diodes, and Praxagoras_, also of Cos,--the last of the Asclepiadæ mentioned in history. Praxagoras was distinguished principally for his anatomical knowledge; like Aristotle, he supposed that the veins originated from the heart, but did not confound these vessels with the arteries, as his predecessors had done, but supposed that they contained only air, or the vital spirit. It has been claimed that he dissected the human body. He laid the foundation of sphygmology, or study of the pulse, since Hippocratic writers rarely alluded to arterial pulsations and described them as of only secondary importance.
The predominating theory in the Island of Cos was that which made health dependent on the exact proportion and play of the elements of the body, and on perfect combination of the four cardinal humors. This was the prevailing doctrine,--i.e., the Ancient Medical Dogmatism, so named because it embraced the most profound dogmas in medicine, and was taught exclusively until the foundation of the school at Alexandria.