A History of Hindu Chemistry Vol 1/The Ayurvedic Period/Chapter 2

by Prafulla Chandra Ray

 

CHAPTER II

Chemistry in the Charaka and the Suśruta

THE CHARAKA

[The subject-matter in the first few extracts in this chapter is practically based upon the Vaiseshika system; see ante pp. 6 et seq.]

The Tastes—The Metals and their Calces

"The object of the tongue is taste. Water and earth are the objective existences in which taste inheres. In its manifestation and as regards particular kinds of it, space, air and light are also its adjuncts. Sweet, sour, salt, pungent, bitter and astringent, these are regarded as the sixfold catalogue of tastes. * * * Objects are again known to be of three kinds, viz., animal products, vegetable products and products appertaining to the earth. Honey, vaccine, secretions, bile, fat, marrow, blood, flesh, excreta, urine, skin, semen, bones, tendons, horns, nails, hoofs, hair, bristles and the bright pigment called Gorochanā,^[1] are used (as drugs) among animal products. Gold, the five metals and their ordure [i.e. their calces, the five metals viz., silver, copper, lead, tin and iron], sand, lime, red arsenic, gems, salt, red chalk and antimony, are indicated as drugs appertaining to the earth."^[2]

A Discourse on the Tastes—their Relationship to the five Primal Elements—the Nature of the Alkali

"Once on a time, the son of Atri, and Bhadrakāpyas Sakuntèya and the full-eyed Maudgalya, and the golden-eyed Kausika, the sinless Bharadvāja otherwise called Kumārasiras, the blessed king Vāryovida, that foremost of all intelligent men, Nimi, the ruler of the Videhas, Vadisa of high intelligence, and Kāmkhāyana-vālhīka, that foremost of all physicians of the Vālhīka country,—these Rishis, all of whom were old in years and learning and all of whom had subjugated their souls, came together to the delightful Chaitraratha woods, desirous of passing a few days in enjoyment and pleasure. As those Rishis conversant with every topic were seated there, the following discourse of grave import took place among them on the subject of the proper ascertainment of the (different) tastes and food.

"There is one kind of taste, said Bhadrakāpya; which persons skilled in the subject regard as are of the five subjects of the senses, viz., that which relates to the tongue. That, again, is not different from water.

"The Brāhmana Sākuntèya said there are two tastes, their virtues being that one of them cuts or removes from the body all bad humours or ingredients, and the other only checks or curbs them.

"There are three tastes, said the full-eyed Maudgalya. Their virtues are cutting, curbing, and both.

"There are four tastes, said the golden-eyed Kausika. They are agreeable and beneficial, and agreeable and non-beneficial, disagreeable and beneficial.

"There are five tastes, said Kumārasira-Bharadvāja. They appertain to Earth, Water, Fire, Air and Ether (or Space).

"There are six tastes, said the royal sage Vāryovida. They are heavy, light, cold, hot, oily and dry.

"There are seven tastes, said Nimi, the ruler of the Videhas. They are sweet, sour, saltish, pungent, bitter, astringent and alkaline.

"There are eight tastes, said Vadisa-Dhāmārgava. They are sweet, sour, saltish, pungent, bitter, astringent, alkaline and that which remains in an unmanifest form.

"The tastes are infinite in number, said Kāmkhāyana, foremost among the physicians of the Vālhīka country, in consequence of the infinite variety of their virtues, operations or effects and methods of corrections (or mixture for adding to their virtues, etc.,).

"The illustrious son of Atri, viz., Punarvasu, said that the number of tastes is truly six. They are sweet, sour, saltish, pungent, bitter and astringent. The source from which these six flow, i. e. their origin, is water. Their operations or effects are of two kinds, viz., cutting and curbing. In consequence, again, of mixture or combination, they become both cutting and curbing at the same time. Agreeable and disagreeable are their divisions that depend upon the likes and dislikes of men. Beneficial and non-beneficial are their powers. The refuge of the tastes are the modifications of the five primal elements (of Earth, Water, Fire, Air and Ether or Space). The tastes, again, depend upon the (original) nature of their refuge, the modifications of that refuge, combinations of the substances that form their refuge, as also place, and time.^[3]

"The virtues or properties (attaching to the tastes) occur in those which constitute the refuge (of the tastes), called objects. Those virtues are heavy, light, cold, warm, oily, dry and others.

"Kshāra (alkali) is so called from its being produced by ksharana (dropping down or straining). This is not a taste. It is, on the other hand, an object. It is, in fact, produced from many kinds of taste. Hence, it has many tastes. Among them, pungent and saline predominate. It is composed of many objects of the senses. It is manufactured with the aid of different processes. *⁠*⁠*⁠*⁠*

"At the outset, however, we shall say something referring to the diversity of objects (which are the refuse of the tastes). All objects are the results of the combinations of five primal elements (viz., Earth, Water, Fire, Air and Ether or Space). As regards Medical Science, object are of two kinds, viz., those endowed with animation and those that are inanimate. The attributes which inhere in objects are sound, &c., heaviness &c., ending with solubility."^[4]

We now quote only a few typical instances of mineral and metallic preparations.

The Five Kinds of Salts

"The five kinds of salts viz., sauvarchala, saindhava, vit, audbhida, with sāmudra." [See Index under the respective headings].

Minerals for External Application

"Sulphate of copper, sulphate of iron, realgar, orpiment and sulphur in combination with vegetable drugs are prescribed for external application in ringworm, eczema, leprosy, &c.,"^[5]

The Eight Varieties of Urine

"The eight varieties of urine are those of the sheep, the goat, the cow, the buffalo, the elephant, the camel, the horse and the ass."^[6]

Preparation of Kshāra (Alkali)

"A young butea frondosa is to be cut to pieces and dried and finally reduced to ashes. The ash is to be lixiviated with four or six times its weight of water and strained (through linen) 21 times."^[7]

Pill Iron Compound

"Into the composition of pill iron compound pyrites and the rust of iron enter."^[8]

A Collyrium

"The ingredients of a collyrium are conch-shell, coral, lapis lazuli, iron, copper, the bone of the frog, sulphide of antimony and the seed hyperanthera morunga."^[9]

[The first five articles are interpreted as meaning the calces thereof.]

Powder of Pearl Compound

"Among the constituents we have, pearl, sulphur, powder of iron, copper and silver."^[10]

[The text does not precisely say whether the metals are to be used as such or as killed by being roasted with sulphur. The Hindu physicians however always take them in the latter sense.]

Iron, Gold and Silver Tonics

"A thin iron plate is to be made red hot and plunged into the decoction of the myrobalans, cow's urine, the solution of "the salts", the solution of the alkali extracted from the ash of butea frondosa; i.e. made red hot and plunged into one of the above liquids at a time. When the iron becomes black like collyrium it is to be powdered. * * *

"The same process to be adopted in the case of gold and silver."^[11]

Rasāyana Defined

"Medicines are of two kinds: the one promotes the strength and vitality of the healthy, the other cures diseases.

"Whatever promotes longevity, retentive memory, health, virility, &c. is called Rasāyana."^[12]

THE SUSRUTA

Preparation and Use of Alkalies and Alkaline Caustics.^[13]

"Of all cutting instruments and accessory cutting instruments, caustics are superior inasmuch as they perform the work of incisions, punctures and scarifications, relieve derangements of the three humours, viz., air, bile and phlegm, and uniformly affect the diseased part to which they are applied. Kshāra (caustics) are so called because they remove diseased parts and destroy the skin and flesh. From being composed of numerous medicines they can affect the three humours. Caustics being white in colour are cooling or of lunar origin.^[14] This origin is not inconsistent with their burning, escharotic and lacerating properties. Being composed of numerous heating medicines, caustics are acrid, hot and pungent. They promote suppuration, destroy parts, improve unhealthy sores and promote granulation, dry up discharge, stop bleeding and abrade the skin. Their internal use removes worms, acidity, phlegm, skin diseases, some poisons and corpulence. Their excessive use causes impotence.

"Alkalies are of two sorts, namely, for external application and internal administration. They are used externally in the skin diseases called kustha, in keloid, ringworm, leucoderma, lepra, fistula-in-ano, tumours, unhealthy ulcers, sinuses, condyloma, moles, chloasma, brown spots on the face, warts, external inflammations, worms, poisons and piles, and in the seven following diseases of the mouth namely, upajihvā (ranula), adhijihvā (tumour on the tongue), upakusa (inflammation of the gum), danta-vaidarbha (inflammation of the gum from injury), and the three sorts of rohinī or inflammation of the throat. In these diseases of the mouth, accessory instruments, in the shape of caustics only, should be used. Alkaline solutions are administered internally in chronic or slow poisoning, abdominal tumours, ascites, loss of appetite, indigestion, disinclination for food, tympanitis, urinary deposits, calculi, internal or deep-seated inflammation, intestinal worms, poisoning. and piles. Alkalies do not agree with children, old and weak people, and persons having a tendency to hæmorrhage from internal organs, or a bilious temperament. They are injurious in fever, giddiness. intoxication, fainting, amaurosis and such other diseases.

"Alkalies for escharotic use are prepared like other alkalies by straining alkaline solutions as elsewhere explained in detail. They are made of three strengths, namely, weak, moderate and strong. He who wishes to prepare alkalies should in an auspicious day in autumn, fasting and in pure body, select a middle-aged, large-sized, uninjured ghantāpātali tree with black flowers (Schrebera swietenioides) growing on an approved spot on a mountain, and address it with certain mantras or incantations as a preliminary ceremony called adhivāsa. Next day the tree should be cut or killed after reciting the following mantra or prayer: "Oh you with great fiery power may not thy strength be lost! Oh you auspicious tree, stay here and accomplish my work. After accomplishing my work you will go to heaven." Then the ceremony of homa, or burning the sacrificial fire, should be performed with one hundred red flowers. The tree should then be cut to pieces and piled in a place free from wind. Some limestone should be placed on the pile which should be set on fire by stalks of Sesamum Indicum. When the fire is extinguished, the ashes of the ghantāpātali tree and the burnt lime should be kept separate. In the same way the following trees may be burnt with their root, branches, leaves and fruits for the preparation of alkalies,^[15] namely:

Kuṭaja		Hollarrhena antidysenterica.
Palāsa		Butea frondosa.
Asvakarna		Shorea robusta.
Pāribhadraka		Erythrina indica.
Vibhītaka		Terminalia bellarica.
Āragvadha		Cassia fistula.
Tilvaka		Symplocos racemosa.
Arka		Calotropis gigantea.
Snuhī		Euphorbia neriifolia.
Apāmārga		Achyranthes aspera.
Pātalā		Stereospermum suaveolens.
Naktamāla		Pongamia glabra.
Vrīsha		Justicia adhatoda.
Kadalī		Musa sapientum.
Chitraka		Plumbago zeylanica.
Pūtīka		Guilandina bonducella.
Indravriksha		Terminalia arjuna.
Āsphota		Salvadora persica.
Asvamāraka		Nerium odorum.
Saptachchhada		Alstonia scholaris.
Agni mantha		Premna serratifolia.
Gunjā		Abrus precatorins.
4 sorts of Kosā		4 varieties of Luffa amara."

Lixiviation of the Ashes

"Thirty two seers of ashes should be stirred or mixed with six times their quantity of water or cow's urine and the mixture strained through cloth. This should be repeated twenty-one times. The strained fluid should then be boiled slowly in a large pan and agitated with a ladle. When the fluid becomes clear, pungent and soapy to the feel, it should be removed from the fire and strained through cloth. The filtrate^[16] being thrown away, the strained fluid should be again boiled. From this alkaline solution take three quarters of a seer."

Rendering the Alkali Caustic

"Then take eight palas each of Banduc nut, burnt limestone, conch shells, and bivalve shells and beat them in an iron pan till they are of the colour of fire. Then moisten them in the same vessel with the above-mentioned three-quarters of a seer of alkaline water and reduce them to powder. This powder should be thrown on sixty-four seers of the alkaline water and boiled with constant and careful agitation by the ladle. Care should be taken that the solution is neither too thick nor thin."

How to Store up the Alkali

"When reduced to proper consistence, the solution should be removed from the fire and poured into an iron jar. The opening or mouth of the jar should be covered, and should be kept in a secluded place. This preparation is called madhyama kshāra or alkaline caustic of middling strength. When the alkaline water is simply boiled to the proper consistence without the addition of burnt shells, &c., the preparation is called mridu^[17] kshāra or weak alkaline solution. The strong alkaline caustic is prepared by boiling the weak solution with two tolahs each in fine powder of such of the under-mentioned ingredients as are available, namely:—

Dantī,	Baliospermun mon anum.
Dravantī	Salvinia cucullata.
Chitraka	Plumbago zeylanica.
Lāngalikī	Gloriosa superba.
Pūtika	Guilandina bonducell.
Kanaka	Salvinia cucullata.
Kshīrī	Cleome felina.
Vachā	Acorus calamus.

"Aconite root, carbonate of soda, asafœtida, black salt and corals.

"This solution is used for bringing to a head or opening abscesses. These three varieties of alkalies should be used according to the state of the disease. In weak persons, the alkaline water without the addition of other caustic ingredients, should be applied to strengthen the parts."

Characteristics of the Good and the Bad Alkali

On this subject there are the following verses:

"Good alkaline caustics should be neither too strong nor too weak. They should be white in colour, smooth and soapy to the touch, should not spread beyond where they are applied, and act rapidly and successfully. These are the eight good properties of caustics. Their bad qualities consist in their being too weak or cool, too strong or hot, too slippery and spreading, too thick or too under-boiled, or they may be deficient in ingredients.

"In applying caustic to a patient suffering from a disease curable by this remedy, he should be made to sit in a spacious place, protected from wind and sun. The physician should then procure the instruments or necessary articles according to the rules laid down in the fifth chapter. He should then examine the diseased part, rub, scarify or scratch it, and then apply the caustic by means of a probe, and wait for the space of time required to utter one hundred words. The diseased part turns black on the application of the caustic which is a sign of its having been burnt. The application of some acid mixed with clarified butter or honey relieves the pain. If from the thickness of the burnt part, it does not fall off, the following application should be thoroughly applied to it, namely, equal parts of tamarind pulp, of the refuse of kānjika (fermented rice water i. e. crude vinegar), sesamum seeds and liquorice root rubbed together into a paste. Sesamum seeds and liquorice root rubbed together with clarified butter promotes granulation in ulcers."

Why the Acid Neutralises the Alkali

"If you question, my son! how is it that the application of the pungent acid of kānjika relieves the burning of the fire-like hot alkaline caustic, then hear the following explanation from me. Alkalies possess all the tastes except that of the acid. The acrid taste prevails in it and the saline one to a less degree (cf. ante p. 28). The sharp saline taste when mixed with acid becomes very mild, and gives up its sharp quality. From this modification of the saline taste, the pain of caustics is relieved just as fire is extinguished by water."

Mild and Caustic Alkalies

It will be noticed that there is a distinct mention of "mild" and "caustic" alkalies in the body of the text. The process of lixiviating the ashes and rendering the lye caustic by the addition of lime leaves very little to improve upon, and appears almost scientific compared to the crude method to which M. Berthelot pays a high tribute:

"Fabrication de la Lessive:—Quatre muids de cendres sont répartis entre deux cuviers, percés de trous au fond. Autour du trou le plus petit, du côté intérieur, mets une petite quantité de foin, pour que la cendre n'obstrue pas le trou. Remplis d'eau le premier des cuviers; recueille le liquide filtré qui en découle pendant toute la nuit et mets-le dans le second cuvier; grade ce qui filtere de ce second cuvier. Mets d'autre cendre (dans un troisième cuvier). Epiuse-la et il se forme une liqueur pareille au nard couleur d'or. Verse-la dans un quatrième cuvier. La liqueur devient piquante et forte: telle-est la lessive particulière." "Coll. d. Alch. Grecs" III. trad. p. 357.

We reproduce the remarks of M. Berthelot on the above: "On a regardé comme modernes les procédés de lixiviation méthodique, usités pour exprimer les cendres et les matériaux salpêtrés: le passage suivant, tiré du manuscrit de Saint-Marc, montre que ces procédés remontent au XIe siècle et sans doute au delà." "Chimie des Anciens" p. 284.

Description of Blood

(Chapter XIV of Sūtrasthānam)

"The four varieties of food derived from the five elements and having the six tastes, the two properties of heat and cold or according to some, eight properties and many qualtities when taken in moderation and thoroughly digested, produces a fine substance imbued with energy and fire. This is called rasa (chyle). The heart is the seat of the rasa or chyle. From the heart it proceeds through 24 arteries, namely, ten ascending, ten descending, and four transverse to all parts of the body. By some unseen cause or destiny, this chyle continually satiates, increases, nourishes and supports the body and keeps it alive. The motion of this chyle throughout the body is inferred form the processes of decline, increase, and diseased condition of the different portions of the body. It may be asked whether this chyle which pervades all the external parts of the body, the three humours, the tissues, including the blood and the receptacles of the secretions, is endowed with the property of heat or cold. As this chyle is a circulating fluid, and as it softens, vitalises, supports and nourishes the body, it should be known to possess the cooling property. This watery fluid no doubt assumes a red colour in the liver and spleen, that is, it is converted into blood in these organs. On this subject there is the following verse:

"The rasa (chyle) of living beings is coloured red by healthy bile. This coloured fluid is called blood. The blood excreted by women and called the menstrual fluid is derived also from this rasa. This menstruation, coming at the age of twelve, ceases at the age of fifty.

"The menstrual fluid is endowed with the property of heat, owing to the womb being possessed of both the properties of heat and cold. Other writers say that the blood of living beings is composed of the five elements. The five qualities of the five elements as seen in blood are as follows, namely, fleshy smell, liquidity, red colour, tendency to trickle or ooze, and lightness.^[18] Blood is produced from chyle, flesh from blood, fat from flesh, bones from fat, marrow from bones, and lastly the semen is produced from marrow. The chyle produced from food and drink nourishes these constituent parts of the body. Living beings are produced from the rasa; hence sensible people should carefully preserve this rasa by conforming to the proper rules of diet and regimen."^[19]

On the Collection of Drugs
(Chapter XXXVIII: Sūtrashānam)

37 classes of vegetable drugs are mentioned which chiefly constitute the Materia Medica. There is only one sloka in which the six metals viz., tin, lead, copper, silver, krishnaloha (iron) and gold, and their calces are recommended.

The Salts

Rock-salt, sea-salt, bit, sauvarchala, romaka and audbhid, &c. (see ante p. 29).

The Alkalies

Yavakshāra (factitious carbonate of potash), sārjikākshāra^[20] (trona or natron); the alkaline solution prepared according to directions given in Ch. XI; and borax.

Internal administration of alkali is recommended for dissolving the stones or gravels (urinary calculi).

Internal use of Lead and Tin

Lead and tin are described as vermifuge—a property also accepted by the later Iatro-chemists.

Powdered tin rubbed for seven days together with the creamy portion of curd is recommended for internal administration.

Minerals for External Application

For the treatment of ulcer an external application of sulphate of copper, sulphate of iron, orpiment and realgar, &c., is prescribed.

Another recipe includes alum-earth, red-ochre, sulphate of copper, yellowish (basic) sulphate of iron, rock-salt, orpiment and realgar.^[21]

Roasting of Iron and other Metals, so as to Render them Fit for Internal Administration.

Thin leaves of cast iron are to be smeared with the levigated powder of "the salt" and heated in the fire of the cow-dung cakes and then plunged into a decoction of the myrobalans and asafœtida. This process is to be repeated 16 times. The leaves are then to be ignited in the fire of the wood of mimosa catechu and afterwards finely powdered and passed through linen of fine texture.

The above process is equally applicable to the roasting of the other metals.^[22]

The Origin of Bitumen

The origin of bitumen is much the same as in the Charaka and the Bower Ms.; the only difference being that, according to Susruta, bitumen is related to six instead of four metals (see below p. 53).

Iron Pyrites

Iron Pyrites are collected on the bank of the river Tāpī, of the lustre of gold and silver respectively (see below under "Rasaratnasamuchchaya", Bk. II, 77-81 and prescribed in the treatments of diabetes, leprosy, &c.

Gold Dust

Gold dust, mixed with lotus seed, honey, &c. is used as a tonic.

The Poisons

The Poisons are classified as animal, vegetable and mineral respectively. Under the last we have Phenasma bhasma^[23] and orpiment.

Use of Mercury

The only references to mercury, which are however very vague, are तारः सुतारः ससुरेन्द्रगापः सर्ब्बैश्च तुल्यः कुरुविन्द गागः; and: रक्तं श्वेतं चन्दनं पारदञ्च काकोल्यादिः क्षीरपिष्टश्च वर्गः।

Note on the Metals and their Salts (अयःष्कृति)^[24]

Six metals are recognised, namely: tin, iron, lead, copper, silver and gold.^[25] The thin leaves of the metals by being plastered over with a paste of "the salts" (see p. 46) including common salt, salt-petre and sulphate of magnesia and afterwards subjected to roasting were no doubt converted into their respective oxides, chlorides or oxychlorides as the case may be. We have thus in the Susruta a crude and imperfect, but all the same potentially modern, process for the preparation of the metallic salts. The much reputed "potable gold" in the shape of the chloride of the metal was probably in this way obtained. It will be interesting to note the successive stages in the evolution of the chemical processes as we proceed. (See below especially under "Chemistry in Rasārnava," where the mixture of the salts is technically named "vida" and consists of green vitriol, alum, common salt, salt-petre, &c.).

The reader will find an analogy in the ancient Egyptian and Greek methods as preserved in the Leyden Parchment, one or two extracts from which cannot fail to be of interest. It may be added by way of explanation that mineral acids being unknown to the ancients they had often to take recourse to the roundabout way of heating metals in combination with a mixture of blue vitriol, copperas, common salt and so on (see under "Mineral Acids") in order to get their salts.

"Ayant pris quatre paillettes d'or, faites-en une lame, chauffez-la et trempez-la dans de la couperose broyée avec de l'eau et avec une autre (couperose) sèche, battez (une partie)...une autre avec la matière mélangée: déversez la rouille et jetez dans..."

"Il y a là deux recettes distinctes. Dans toutes deux figure le sulfate de cuivre plus ou moins ferrugineux, sous les noms de chalcanthon ou couperose et de sory. La seconde recette semble un fragment mutilé d'une formule plus étendue. La première présente une grande ressemblance avec une formule donnée dans Pline pour préparer un remède avec l'or, en communiquant aux objects torréfiés avec lui une propriété spécifique active, désignée par Pline sous nom de virus * * * ...ce qui complète le rapprochement entre la formule de Pline et celle du papyrus. Voici les paroles de Pline:

"On torréfie l'or dans un vase de terre, avex deux fois son poids de sel et trois fois sonpoids de misy; puis on répète l'opération avec 2 parties de sel et 1 partie de la pierre appelée schiste. De cette facon, il donne des propriétés actives aux substances chauffées avec lui, tout en demeurant pur et ihtact. Le résidu est une cendre que l'on conserve dans un vase de terre."

"Pline ajoute que l'on emploie ce résidu comme remède. L'efficacité de l'or, le plus parfait des corps, contre les maladies et contre les malfices est un vieux préjugé. De là, au moyen âge, l'idée de l'or potable. La préparation indiquée par Pline devait contenir less métaux étrangers à l'or, sous forme de chlorures ou d'oxychlorures. Renfermait-elle aussi un sel d'or? A la rigueur, il se pourrait que le chlorure de sodium, en présence des sels basiques de peroxyde de fer, ou même du bioxyde de cuivre, dègageât du chlore, susceptible d'attaquer l'or métallique ou allié, en formant du chlorure d'or, ou plutôt un chlorure double de ce métal. Mais la chose n'est pas demontrée. En tous cas, l'or se trouve affiné dans l'opération précédente."^[26]

 

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1. Concretions found in the gall bladder of the ox.
2. A. C. Kaviratna's Translation of "Charaka Samhitá," pp. 6-7.
3. The modifications of the five primal elements constitute the refuge of the tastes. Every substance is formed by modifications of those elements. What is said, therefore, is that material substances are the refuge of the tastes, i.e. the tastes inhere in them.
4. Kaviratna's Trans., pp. 295-99.
5. Sútra, Ch. III, 4-5.
6. Ibid, Ch. I, 43.
7. Chikitsá, Ch. XXIII, 26.
8. Ibid, Ch., XVI 28.
9. Ibid, Ch. XXVI, 123.
10. Chikitsá, Ch. XVII, 40.
    The references are according to the edition of Kavirajes D. N. Sen and U. N. Sen.
11. Chikitsá. Ch. I. 5, pp. 497-98.
12. Ibid Ch. I. pp. 2-6.
13. We have adopted Udoy Chand Dutta's Translation of Chs. XI and XIV with certain corrections here and there.
14. The reader will not fail to notice that silver nitrate is, in the language of Western Alchemy, named lunar caustic.
15. Cf. Rasārnava, below, where the standard "plant ashes" are enumerated.
16. This is evidently a mistake. According to the original text, it should be "the dregs" i. e. the precipitate.
17. "Mridu" may be rendered more accurately as "mild."
18. Cf. ante pp. 6-7-under Vaiseshika Philosopy.
19. The reader may compare the above theories on the Chemistry and Physiology of Digestion and Nutrition with those of Geber. Vide "Traité d'Alchimie Arabe," trad. pp. 201-3.
20. From the time of the Charaka and the Susruta, Hindu Pharmacy has always recognised these two alkalies as distinct.
21. Chikitsitasthānam Ch. XIX, 37, ed. J. Vidyáságara.
22. See Note on the "Metals and their Salts" p. 48
23. It is sometimes taken to mean white arsenic; "but it is very doubtful if Susruta meant any native white arsenic by it. The derivation of the term implies that it was obtained by roasting some sort of stone or ore." Dutt.
24. अत ऊर्द्धमयस्कृतीर्वक्ष्यामः। तीक्ष्यलोहपत्राणि तनूनि लवनवर्गप्रदिप्तानि गोमयाग्निप्रतप्तानि *** सूक्ष्मचूर्णानि कारयेत्। Chikit., Ch. X, 9.
25. त्रप्वादिनान्तु लोहानां षण्णाम्। Chikit., Ch. XIII, 3.
    त्रपुसीसताम्ररजतकृष्णलोहसुवर्णानि। Sütra., Ch., XXXVIII, 56.
26. "Coll. des Anciens Alch. Grecs," Vol. I., pp. 14-15.