Page:A Short History of Aryan Medical Science.djvu/123

VII.] sweet. A sweet Vipaka promotes phlegm but lessens wind and bile ; a sour Vipaka increases bile but decreases wind and phlegm ; while a Vipaka that is pungent gives rise to disorders of wind and subdues those of phlegm and bile. Native Pharmacodynamics treat of the changes which each medicinal agent undergoes in the organism. In determining the property of an agent and the chemical changes that affect it, the ancients have ascertained which of the five constituent elements — ether, wind, fire, water, and earth — is predominant in its formation. The five elements have been characterised by their respective qualities of lightness, dryness, sharpness, unctuousness and heaviness. It may be noted here, by way of parenthesis, that this elemental theory precisely accords with that of Plato, Hippocrates, and Pythagoras, though the first two do not seem to recognise ether as an elemental constituent. To determine the proportion of the several elements in the formation of a medicinal drug, and to describe the subsequent changes it undergoes in the living economy, presupposes some knowledge, on the part of the old Indian writers, of chemical analysis and the process of decomposition.