The five fundamental principles * such as the earth (Kshithi), water (Apa), fire (Teja), air (Marut) and Sky (Vyoma) enter into the composition of all substances in the world, and the predominance of any of them in a particular substance determines its character. Accordingly a thing is denominated as a substance of dominant earth principle, or one marked by a predominance of fire, air or ether.
A thing or substance, which is thick, pithy, compact, dull, immobile, rough, heavy (hard to digest), strong smelling and largely has a sweet taste marked by a shade of astringent, is called a substance of dominant earth (Parthivam) matter. Such a thing increases the firmness, strength, hardness and rotundity of the human body, and is possessed of gravity (the virtue of moving the bowels).
Similarly, a thing or substance, which is cold, moist, glossy, devoid of keenness, takes time to be digested, is mobile, compact, soft, slimy, sappy, and is largely endued with an acid, saline or sweet taste marked by a shade of astringent, is called a substance of dominant water (Apyam) principle. Such a thing soothes and imparts a glossy character to the body, keeps it moist, favours the adhesion of its parts, and increases its liquid contents.
* These may be translated as Solid, Liquid, Gas, Ether, and Etherion in the parlance of modern science.
A thing or substance, which is heat-making, pungent and keen, subtle in its essence, permeates the minutest capillaries, and is dry, rough, light, and non-slimy in its character and has strong properties and a taste which is largely pungent marked by a shade of saline, is called a substance of the dominant principle of fire (Taijasam). Such a thing naturally evinces an up-coursing tendency in the body, produces a burning sensation in its inside, helps the process of digestion and spontaneous bursting (of abscesses), increases the temperature of the body, strengthens the eyesight, improves the complexion and imparts a healthful glow to it.
A thing or substance, which is subtle in its essence, and is dry, rough, light, cold and non- slimy, increases tactual sensation and is endued with a largely astringent taste marked by a shade of bitter, is called a substance of the dominant principle of air (Vayaviyam). Such a thing removes the slimy character of the internal organism, produces lightness, dryness and emaciation of the body, and increases the speculative or contemplative faculty of the mind.
A thing or substance, which is smooth, unctuous, and is subtle in its nature, soft or pliant in its consistency, expansive in the internal organism), porous, soundy and non- slimy in its character without any definite taste, is called a substance of the dominant principle of sky (Akashiyam). Such a substance produces softness, lightness and porosity of the body.
It may be inferred from the foregoing illustrations that there is not a single substance in the world but is endued with certain curative virtues. Drugs or substances, used in specific combinations and according to the indications of a disease under treatment, prove curative in virtue of their native virtues and potencies. The time, during which a drug or a medicine exerts its curative virtues, is called its Kala or the period of action. That which immediately results from the use or application of a medicinal remedy is called its Karma or physiological action. The principle, in virtue of which the action is performed, is called its potency or Viryam. That, in which the action takes place, is called its receptacle or Adhikaranam. The means by which it is effected is called its agency or Upaya, while that what it accomplishes is called its therapentic effect or Phalam.
Of these the drugs of purgative virtue are possessed 48 of attributes which specifically belong to the earth and water. Earth and water are heavy, and naturally gravitate downward owing to their heaviness. Hence it is inferred that purgative drugs are largely endued with the specific attributes of earth and water, in virtue of which they are more strongly attracted towards the centre of the earth (gravity). Drugs endued with emetic properties are possessed of attributes which form the characteristics of fire and air. Fire and air are light, and naturally ascend upward owing to their lightness. Hence it is inferred, that emetic (Vamana) drugs are largely possessed of attributes, which are upcoursing in their nature. Drugs or substances endued with both emetic and purgative virtues are characterised by attributes belonging to both the aforesaid elements (earth and fire).
Drugs, which soothe the deranged bodily humours, are permeated with qualities which specifically belong to the principle of the sky. Astringent (Sangrahaka) drugs are endued with attributes, which specifically belong to the air owing to the drying character of the latter element. Appetising (Dipana) drugs are largely possessed of attributes which belong to the material principle of fire. Lekhana (Liquefacient) drugs or substances are endued with attributes which belong to fire and air. Constructive or restorative (Vringhanam) drugs or substances are endued with attributes which specifically belong to earth and water. These inferences should be carefully remembered at the time of prescribing medicines.
The deranged bodily Vayu readily yields to the curative efficacies of drugs possessed of attributes, specifically belonging to the earth, fire and water, while the deranged Pittam is speedily soothed or restored to its normal state by drugs having attributes, specifically belonging to the earth, water and air. Similarly, the deranged Kapham is pacified by drugs possessed of attributes which characterise the sky, fire and air.
The bodily Vayu is increased by the use of drugs possessed of attributes which specifically belong to the sky and air, while the Pittam is increased by the use of those which are largely endued with the specific attributes of fire. The bodily Kapham of the body is increased by the use of drugs which are largely endued with the specific attributes of the earth and water. Thus having ascertained the dominant attributes of drugs, a physician should use them for the pacification of two or more of the deranged humours of the body according to the exigencies of a case.
Of the eight-fold potencies of a drug, such as cooling, thermogenetic, oleaginous, heavy, parchifying, plastive, keen and slimy, keenness and thermogenetic potency should be ascribed to the attributes of fire; cooling potency and that of engendering slime, to the predominance of the attributes of water in a drug or substance; oleaginousness, to the predominance Of the attributes of the earth and water; plastive potency, to the predominance of the attributes of water and the sky; parchifying potency, to the excess of the attributes of air; non-slimy potency (Vaishadyam), to the predominance of the attributes of earth and air; and heavy and light digestion, to the same cause.
Of these, oiliness and thermogenetic potency prove curative in respect of the deranged Vayu, while cooling potency, plastive potency, and that of engendering slime subdue the deranged Pittam. Keenness, parchifying and non-slimy potencies conquer the deranged Kapham. Substances, which are heavy in digestion, destroy the deranged Vayu and Pittam, while those which are light in digestion (easily digestible substances) prove curative in respect of the deranged Kapham.
Of these, softness, coldness and heat may be perceived by touch. The properties of sliminess and its opposite may be perceived by the eyes and touch. The properties of dryness and oiliness of a drug may be perceived with the eyes; keenness of a drug from the fact of its producing pain in the mouth; and [heat and cold, by the sensation of comfort (pleasure) or discomfort - A. Text] The fact of heavy (insufficient) digestion should be inferred from the frequent passing of stool and urine, as well as from the expectoration of Kapham, while the contrary should be presumed from the constipation of the bowels, retention -of urine and disorders of the abdominal Vayu (flatulence, distension of the abdomen, etc.). A specific taste is detected in material principles of similar properties. As for example, a drug or a substance, which is heavy and endued with a sweet taste, should be deemed as belonging to the group of the earthy matter (largely possessed of attributes characterising earth-matter). Similarly, a substance, which is sweet and oily in its character, should be regarded as belonging to one in which the principle of water predominates.
Properties, which characterise drugs and substances, may be as well found in a human organism, and the normal continuance, aggravation or diminution of the deranged humours is due to the action of the drugs (substances).