The function of the »Pittam consists in metamorphosing the chyle, through a graduated series of organic principles, to a protoplasmic substance like sperm in men, and the ovum in women. Thus we see that the Pittam of the Ayurveda corresponds to metabolism of Western physiology. But by a confounding carelessness of terms the excreted portion of Rasa and blood though ultimately connected with those normal physiological processes has been respectively styled as the Doshas or defiling principles of Kaphah and Pittam. Again, as in the case of soil, the terms Vayu, Pittam and Kaphah are extended to denote magnetism, kinetic energy and humidity of its molecules. The circulation of blood is connected with the Pittam, while the circulation of lymph chyle (Rasa) is related to Shleshma the two combinedly forming what is called the sustentative function of the Western Physiology.
The term Pittam, which, by its etymology, signifies the agent of metabolism, has been loosely used by our Ayurvedic physiolgists to denote two different organic principles from an observed similarity in their nature and functions. Pittam in Sanskrit means both bile and metabolism of tissues as well as the bodily heat which is the product of the latter.
Hence a few commentators lean towards the view that Pittam is the heat incarcerated in the bile, and the principal agent in performing digestion (1). The real import of the term may be gathered from the five sub-divisions of the Pittam, made by our Rishis according to their functions and locations, and which are called the Pachaka, Ranjaka, Sadhaka, A'lochaka and Bhrajaka. All metabolic processes in the organism, whether constructive or destructive, are called Pittam, which is said to be in the products of those processes whether serum, bile, blood, albumen, etc., which are either essential to the substance of the body, or to the proper performance of any organic function. Hence we learn that Pittam is latent in Lasika (Serum), blood, lymph chyle, albumen etc., and in the organs of touch and sight. In other words, metabolism goes on in those principles and regions of the human organism (1) either as a sustentative or as a cognetic physiological process. First, we have the Pachakagni or the heat of digestion, which is situated in the region between the stomach and the intestines; (2) and being a liquid fire or fluid heat incarcerated in the secretions of the liver (bile), it is primarily concerned in digesting the four kinds of food (as they meet it in the abdomen). Thus we see that the Pachakagni of our Ayurveda is the same as the bile of Western physiology, its other function being to differentiate (precipitate) the nutritive essence of the food from its unutilisable portion, and to act as an excrementitious matter. It is this Pittam, which makes metabolism in other parts of the body possible, (3) by helping the organism in acquiring fresh energy.
Bagbhat (Sutra Sthanam ch. XII.)
(2) The bile assists in emulsifying the fats of Ihe foods, and thus rendering them capable of passing into the lacteals by absorption *. The bile has been considered as a natural purgative * * * The bile appears to have the power of precipitating the gastric proteoses and peptones, together with the pepsin, which is mixed up with them. * * *As an excrementitious substance, the bile may serve as a medicine for the separation of certain Highly carbonaceous substances from the blood.
Kirk's Physiology Ch. XIII. pp 377-378.
Bagbhat Sutra ch. XII.
The second kind of Pittam is called Ranjaka or pigment Pittam from the circumstance of its imparting the characteristic colour to the lymph chyle as it is transformed into blood by coursing through the liver and spleen, where it is located (1).
The third kind of Pittam (Sadhaka) is situated in the heart, and indirectly assists in the performance of cognitive functions in man by keeping up the rhythmic cardiac contractions (2). Perhaps it is this view of the heart's contraction that predisposed many of our ancient physiologists to hold it as the seat of cognition (Vuddhi Sthanam). (I)
(1)A. The colouring matter of the bile is derived from and is closely related to that of blood, since the qualities of the bile pigment secreted are markedly increased by the injection of substances into the veins which are capable of setting free haemoglobin Kirk's Physiology - (Metabolism in the liver.) Ch. XII. p. 505.
B. There seems to be a close relationship between the colouring matters of the blood and of the bile, and between these and that of urine (urobilin) and of the feces - Ibid Ch. VIII. p. 376.
C It seems probable that the spleen, like the lymphatic glands, is engaged in the formation of blood corpuscles. For it is quite certain, that the blood of the splenic vein contains an unusually large number of white corpuscles, † † † In Kottiker's opinion, the development of colourless and also coloured corpuscles of the blood, is one of the essential functions of the spleen, into the veins of which the new formed corpuscles pass, and are conveyed into the general current of the circulations.
Ibid. Ch. XII.
(2) a. The contraction (of the heart) can not be long maintained without a due supply of blood or of a similar nutritive fluid. * * * The view that is at present taken of the action of the heart is * * that in heart muscle, as in protoplasm generally, the metabolic processes are those of anabolism or building up. which takes place during diastole of the heart * * * and the katabolism or discharge which is manifested in the contraction of the heart. Kirk's Physiology (metabolism of the heart). Ch. VI.
Bagbhat Sutra. Ch. XII. 13.
The fourth, which is the Alochaka or the Pittam of sight; indicates the metabolic process in the substance of the retina (Drishti) which gives rise to visual sensation. (2;
The fifth is the Bhrajakagni or the Pittam in the skin which produces perspiration or helps exudations from the skin by evaporation. In short it is the Pittam which keeps active, under certain circumstances, the secretions from the sweat and sebaceous glands of the human skin.