The actions of living matter vary and so may be reduced to three categories. They are either - (1), functions which affect the material composition of the body and determine its mass, which is the balance of the processes of waste on one hand and those of assimilation on the other. Or (2), they are functions which subserve the process of reproduction which is essentially the detachment of a part endowed with the powers of developing into an independent whole, or (3), they are functions in virtues of which one part of the body is able to exert a direct influence on another, and the body, by its parts as a whole, becomes a source of molar motion. The first may be termed Sustentative, the second Generative, and the third Correlative functions. The above is the sum and substance of the works which a living matter has to perform. But setting apart the processes of reproduction as a subject for future discussion, we shall now try to examine what the other two functions are as understood by Oriental thinkers. In the Mahabharatam the Prana vayu is described as a force, akin to electricity. It is somewhat like a flash of lightning (1). This fact at once shows the errors of confounding Prana vayu with an effete material - with gases generated during the processes of digestion. Shushruta describes it as a force, (2) which sets the whole organism into motion. Self-evolved, it acts as the principal factor that determines the genesis, continuance and disin-tegration of the living body. It is the primary cause - an all-in-all that governs our organic as well as our cognitive faculties. Its special feature is that the vibration, that is produced in it, instead of travelling like light in a transverse direction, takes a course as the controller of the correlative functions of the system. It maintains an equilibrium between the Pittam and Shleshma which are said to be inert. (1) But for this adjustment the living body would stand in imminent danger of being consumed like fuel by its internal heat or fire. Taking into consideration the various functions the living body has to perform, Sushruta attempts a classification of Vayu into Prana, Udana, Samana, Vyana and Apana, which, in detail correspond to the divisions of functions performed by the Cerebro-spinal and Sympathetic nerves of the Western physiology. Tantric literature abounds in the descriptions of the Nadichakras (nerve plexuses) and contains a more detailed account of the motor, sensory, and mixed nerves according to their differences in their functions and relations. In short, the term Vayu may not only be rightly interpreted to mean the nerve force, but is often extended to include any kind of electro-motor or molecular force (as when we speak of the Vayu of the soil), though the term is loosely applied now to signify gas or air. The Rishis of yore gave the name of Vayu to the bodily force in the absence of any suitable nomenclature, little suspecting that it might be confounded with the atmospheric air by the foreign translators of their works.
Mahabaratam. Shanti Parva S. 39.
(2) Force may be defined as that which tends to produce motion in a body at rest, or to produce change of motion in a body which is moving, - Daschanel.
Inert is Pittam, inert is Kaphah, inert are the Malas & Ohatus Like clouds, they go wherever they are carried by the Vayu.