1. The Nature of the Tridhatus

263 THE PHYSIOLOGICAL AND THE PATHOLOGICAL CONCEPTS OF TRIDOSH THEORY I. NATURE AND PHYSICAL PROPERTIES OF THE TRIDOSHA The fundamental principle underlying the Ayurvedic system of medicine is that of the Tridosa. There are three Dosas-Vayu, Pitta and Kapha I which, when in equilibrium, keep the body sound, but which when vitiated, either singly or in combination, bring about diseases. The method of treatment would therefore be to bring the vitiated Dosas back to the normal state, so that three Dosas are again in equilibrium. When the three Dhatus Vayu, Pitta and Kapha remain normal and undisturbed, the body is at ease and there is no disease. (1) THE NATURE OF THE TRIDHATUS Vayu, Pitta and Kapha are three substances found in the body. Of these, Vayu is of the nature of a gas, life force, Pitta is of a fiery nature of Kapha or Slesman is of a watery nature (Sushruta Samhita Su. 42:4). The elder Vagbhate, however, says that Vayu is derived from Vayu and Akasa, Pitta is Agneya i.e. predominently fiery and Slesman is derived from water and earth(Ashtanga Samgraha Su.20). This means that although Vayu, Pitta and Kapha are Panchabhautika, we may regard the Vayu as motive force in the predomently of the nature of a gaseous body, with a little admixture of the properties of ether. The most prominent

264 characteristic of Pitta being its property of heat and its power of digestion, it has been called Taijasa or Agneya. As regards Kapha, we shall see that it has properties which are similar to those of water and earth. The terms Vayu, Pitta and Slesman are derived respectively from the roots 'Va' to move or excite, 'tap' to heat and 'Slis' to embrace (Sushruta Samhita Su.21:5). From this, we infer that the natural attributes of Vayu are motion and the power of imparting that motion to other bodies, that of Pitta heat and those of Slesman or Kapha union and integration. Although the body is made up of the five Blutas, yet for the convenience of Ayurveda, it is said that Dosa, Dhatu and Mala are the roots of the body (S.Seu.15:3). The Dosas are three in mumber Kapha. Dhatus are seven - Vayu, Pitta and Rasa (Chyle), Rakta (Blood), Mamsa (Flesh), Medah(Fat), Asthi (Bone), Majja (Marrow) and Sukra (Semen). The Malas are excreta the sweat, urine, faces etc. The word Dhatu is derived from the root 'Dha' but their special seats in the normal states are respectively the lower, middle and upper portions of the body. Thus as three pillors can support a building, so also these substances support and maintain the body, and because they make the body firm they are called 'Sthuna' or pillars (Sushruta Samhita Su.21:3).

265 Vayu, Pitta and Kapha are called Dhatus, because when in the normal state, they sustain the body. Susruta has described these three as the causes of production of the body. He also says, "The body cannot be produced without Kapha or Pitta or Vayu or without food. It is these substances that sustain the body" (SS.Su. 21:4). Vayu, Pitta and Kapha are called Dosas or vitiaters, because it is these three that vitiate other substances of the body. Susruta has included blood in the category of Dosas, but that is in and indirect sense. His work being mainly one on Surgery, he has to deal frequently with blood. But blood cannot vitiate another substance independently by itself. It is the deranged Vayu, Pitta or Kapha that first vitiate the blood. This impure blood, being thus associated with one or the other of the vitiated Dosas has now the power of deranging another substance, so blood cannot be strictly called a Dosa. Vayu, Pitta and Kapha are also called Mala or filth or waste-product, because they can make the body unwholesome and also because they are produced as waste-matter during the process of digestion. But Vayu, Pitta and Kapha are generally described as Dosas, because they have a natural tendency of vitiating other substances.