Part 10 - The Circulatory and the Nervous System

The names śirā (also hirā) and dhamani , of two different kinds of channels in the body, seem to have been distinguished at a period as early as the Atharva-Veda^[1]. The Bṛhad-āraṇyaka Upaniṣad describes the hitā nāḍīs of the heart as being as fine as a thousandth part of a hair, and they are said to carry white, blue, yellow and green liquids; Śaṅkara, commenting on this, says that these various colours are due to the various combinations of vāta, pitta and śleṣman which the nāḍls carry^[2]. He states that the seventeen elements (five bhūtas, ten senses, prāṇa and antaḥkaraṇa) of the subtle body, which is the support of all instinctive desires, abide in these nāḍīs.

In Bṛhad-āraṇyaka , IV. 2. 3 it is said that there is the finest essence of food-juice inside the cavity of the heart; it is this essence which, by penetrating into the finest nāḍīs, serves to support the body. It is surrounded by a network of nāḍīs. From the heart it rushes upwards through the extremely fine hitā nāḍīs, which are rooted in the heart.

Chāndogya, viii. 6. 6 speaks of 101 nāḍīs proceeding from the heart, of which one goes towards the head^[3]. In Muṇḍ. 11. 2. 6 it is said that, like spokes in a wheel, the nāḍīs are connected with the heart. Praśna, ill. 6 and 7, however, says that in the heart there are one hundred nāḍīs and in each of these are twenty-two hundred branches and the vyāna vāyu moves through these.

The Maitrī Upaniṣad mentions the suṣumṇā nāḍī proceeding upwards to the head, through which there is a flow of prāṇa^[4]. None of these passages tell us anything definite about the nāḍīs. All that can be understood from these passages is that they are some kind of ducts, through which blood and other secretions flow, and many of these are extremely fine, being about the thousandth part of a hair in breadth.

The naḍa, or hollow reed, is described in the Ṛg-Veda (viii. 1. 33) as growing in ponds and in the Atharva-Veda (iv. 19. 1) as being vārṣika, or “produced in the rains.” This word may have some etymological relation with nāḍī^[5]. In another place it is said that women break naḍa with stones and make mats out of them^[6]. The word nāḍī is also used in the Atharva-Veda in the sense of “ducts^[7].”

In Atharva-Veda, V. 18. 8 the word nāḍikā is used to denote the speech organ ( vāk). The word dhamani is used in Ṛg-Veda, 11. 11. 8 and is paraphrased by Sāyaṇa as sound (śabda) and by Macdonell as “reed” or “pipe^[8].” If Sāyaṇa’s explanations are to be accepted, then in A.V. 11. 33. 6 the word snāva means fine śirās (sūkṣmāḥ-sirāḥ) and dhamanī the larger ducts (dhamani-śabdena sthūlāḥ). In vi. 90. 5 one hundred dhamanis are said to surround the body of a person suffering from colic or gout (śūla), and Sāyaṇa paraphrases dhamani here as nāḍī. In Chāndogya, in. 19. 2, the rivers are said to be dhamanis (yā dhamanayas tā nāḍyaḥ), and Śaṅkara paraphrases dhamanī as śirā. I have already referred to the use of the word hirā in the Atharva-Veda; the word is also used in the Ṛg-Veda^[9].

The above references show that nāḍīs, śirās (or hirās) and dhamanīs were all ducts in the body, but sometimes the nāḍīs or śirās had also the special sense of finer channels, whereas the dhamanīs were the larger ducts. I shall now come to Caraka: it will be found that there was not much advance towards a proper understanding of the significance of their distinction and functions.

Caraka plainly regards dhamanīs, śirās and srotas (secretory currents) as ducts and thinks that different names are applied to them on account of their different functions. He says that the roots of the ten dhamanīs are in the heart. These carry throughout the body the ojas, by which all people live and without which they all die. It is the essence by which the foetus is formed, and which goes to the heart at a later stage, when the heart is formed; when it is lost, life also ceases to exist; it is the essence of the body and the seat of the prāṇas. These ducts are called dhamanīs, because they are filled with chyle from outside; they are called srotas, because the chyle, etc. which nourish the body are secreted (sravaṇāt) out of these; and they are called śirā, because they go (saraṇāt śirāḥ) to the different parts of the body^[10]. The ten dhamanīs spread out in manifold branches throughout the body. In the Caraka-saṃhitā srotas means properly the path through which the successive evolutionary products of the body-constituents (dhātus) or other kinds of secretion run and accumulate together with elements of their own types^[11].

Cakrapāṇi explains it thus: The transformation into blood takes place in connection with chyle (rasa). The coming together of rasa with blood at a different part of the body cannot take place without a path of transmission, called srotas. So the transformation of dhātus takes place through the function of this path of transmission. So for each kind of product there is a separate srotas. Vāyu, pitta and kapha may be said to go about through all the srotas, though there are, no doubt, special channels for each of the three^[12].

Gaṅgādhara, however, takes the srotas as being the apertures through which the dhātus and other waste-products flow^[13]. In whatever way it may be looked at, the srotas is, according to Caraka, nothing but the duct of the dhamanīs.

Caraka opposes the view of those who think that the body is nothing but a collection of srotas, for the simple reason that the substances which pass through these srotas and the parts of the body where they are attached are certainly different from the srotas themselves. There are separate srotas for the flow of prāṇa, water, food-juice, blood, flesh, fat, bony materials, marrow, semen, urine, excreta and sweat; vāta, pitta and śleṣman, however, flow through the body and all the channels (sarva-srotāṃsi ayana-bhūtāni). For the supply of materials for the suprasensual elements of the body, such as manas, etc., the whole of the living body serves as a channel^[14].

The heart is the root of all prāṇa channels, i.e. the channels of the prāṇa vāyu ; for vāyu in general moves through all parts of the body. When these are affected, there is either too much or too little respiration; the respiration may be very slow or very quick, and it is attended with sound and pain. From these signs therefore one can infer that the prāṇa channels have been affected.

The source of water channels is the palate, and the seat of thirst is in the heart (kloma)^[15]. When these are affected, the tongue, palate, lips, throat and kloma become dried up, and there is great thirst.

The stomach is the source of all currents carrying food, and, when these are affected, there is no desire for food, but indigestion, vomiting and the like.
The heart is the source, and the ten dhamanīs are the paths, of the chyle (rasa) currents.
The liver and spleen are the source of blood currents.
The tendons and skin are the sources of flesh currents.

The kidneys are the sources of fat channels;
fat and pelvis, of bone channels;
the bones and joints, of marrow channels;
the testes and penis, of semen channels;
the bladder, the pubic and the iliac regions, of urine channels;
the intestines and the rectum, of the excreta channels,
and the fat and pores of hairs, of perspiration channels^[16].

It is curious, however, to note that, in spite of the fact that here the śirās and dhamanīs are regarded as synonymous, their number is differently counted in iv. 7. 13, where it is said that there are two hundred dhamanīs and seven hundred śirās , and the finer endings of these are counted as 29,956. It is reasonable to suppose, in accordance with the suggestions found in theAtharva-Veda, that, though the dhamanīs and śirās were regarded by Caraka as having the same functions, the former were larger than the latter^[17].

Gaṅgādhara, in commenting on this passage, says that śirās, dhamanīs and srotas are different on account of their being different in number and of their having different functions and different appearances. It is well known that a distinction between śirās and dhamanīs is drawn by Suśruta, to which I shall presently refer, but Caraka positively denies any such distinction; and this is accepted by his commentator Cakrapāṇi also^[18]. Gaṅgādhara is unable to point out any passage in Caraka to prove his opinion or to state more explicitly what is the difference of functions and appearances between the dhamanīs and śirās . In fact Gaṅgādhara’s remarks are directly borrowed from Suśruta, 111. 9. 3, without acknowledgment, and it is very surprising that he should not know the difference of views on this point between Caraka and Suśruta and should try to support Caraka by a quotation from Suśruta on the very point on which they materially differ.

Suśruta refers to Caraka’s view that śirās, srotas and dharmanīs are the same and opposes it, saying that they are different in appearance, number and functions. Ḍalhaṇa, in explaining this, says that the śirās carry vāta , pitta , śleṣman , blood, etc., and are rosy, blue, white and red, whereas the dhamanīs that carry sense-im-pressions of sound, etc. have no distinctive colour, and the srotas have the same colour as the dhātus which flow through them. Again, the principal śvrās are forty in number, the principal dhamanīs twenty-four and the principal srotas twenty-two in number.

The śirās permit us to contract or expand our limbs or perform other motor functions, and they allow the mind and senses to operate in their own ways and serve also to fulfil other functions of moving rapidly (prasyandana), etc., when vāyu works in them. When pitta flows through the śirās, they appear shining, create desire for food, increase digestive fire and health. When śleṣman passes through them, they give an oily appearance to the body, firmness of joints and strength. When blood passes through them, they become coloured and filled also with the different dhātus and produce the sense-cognition of touch. Vāyu , pitta, śleṣman and blood—any one of these may flow through any and every śirā^[19].

The dhamanīs are more like sensory nerves, since they carry sensations of sound, colour, taste and smell

(śabda-rūpa-rasa-gandha-vahatvādikaṃ dhamanīnāni).

The srotas carry prāṇa, food, water, chyle, blood, flesh and fat^[20]. It is on account of their close proximity, similar functions, fineness (saukṣmyāt), and also because of the fact that they have been referred to in similar terms by older authorities, that they have sometimes been regarded as performing the same work, though their functions are really different^[21]. Ḍalhaṇa, in explaining this, says that, as, when a bundle of grass is burning, the burning of each separate blade of grass cannot be perceived on account of their contiguity, so the śirās, dhamanīs and srotas are situated so close to one another that it is very difficult to observe their separate functions and work. Śirā, srotas , mārga, kha and dhamanī are the general names used to denote the canals or ducts of the body^[22]. It is on account of the similarity of action of all these ducts that their functions are sometimes confused.

The dhamanīs start from the navel; ten proceed to the upper part of the body, ten to the lower part and four crosswise (tir-yag-gāḥ). Those ten which go to the upper part of the body, branch out, are divided into three classes, and are thirty in number. Of these there are altogether ten for carrying vāta , pitta, kapha , śoṇita and rasa, two for each; there are eight for carrying śabda, rūpa , rasa and gandha, two for each; there are two for the organ of speech, two for making noise (ghoṣa), as distinguished from speech; two for going to sleep, two for being awake; two for bearing tears, two for carrying milk in women, and it is the same two dhamanīs that carry the semen in men. It is by these dhamanīs that the body on the upper side of the navel (e.g. sides, back, chest, shoulders, hands, etc.) is held fast to the lower part. The carrying of vāta , etc. is the common quality of all these dhamanīs.

Those dhamanīs which branch out downwards are thirty in number. They eject vāta, urine, excreta, semen, menstrual blood, etc. downwards. They are connected with the place of pitta (pittāśaya), draw downwards the materials not fit for being absorbed, and nourish the body with the assimilable products of digestion. The dhamanīs connected with the pittāśaya carry the food-juice throughout the body, as soon as it is digested by the action of heat, by supplying it to the upper circulatory dhamanīs and through them to the heart, which is designated as the seat of rasa (rasa-sthāna)^[23].

Ten dhamanīs carry

• vāta,
• pitta,
• śoṇita,
• kapha
• and rasa ;

two, connected with the intestines, carry the food-juice; two carry water; two are connected with the bladder for ejecting urine; two are for the production of semen (śukra-prādur-bhāva), two for its ejection, and it is these which regulate the menstrual flow in the case of women; two, connected with the larger intestines, eject the excreta; there are eight others which carry perspiration. It is by these dhamanīs that the intestines, waist, urine, excreta, rectum, bladder and penis are held together.

Each of the other four dhamanīs , which go crosswise (tiryag-gāḥ), has hundreds and thousands of branches, which, innumerable as they are, are spread all over the body, like so many windows; their mouths are at the holes of the hairs, through which perspiration goes out and which nourish the body with rasa, and through these the effective principles (vlrya) of oil, watery sprinklings, ointments, etc. enter the body after being acted on by bhrājaka (heat of the skin)^[24]. It is again these which carry the pleasurable and painful sense-impressions of touch^[25]. The dhamanīs direct the five senses to the five sense-objects for their cognition. There is the cognizer (mantṛ) and the manas organ; the dhamanī which is connected with manas on one side and the dhamanīs which carry the different sense-impressions on the other make the sense-data cognized by the self^[26].

The various sensory and motor dhamanīs are further named in Suśruta, in. vi. 28. Down below the back of the ear there are two dhamanīs, called vidhura, which, when injured, produce deafness; inside the two nostrils there are the two dhamanīs called phaṇa which, when hurt, arrest the sensation of smell. Below the eyebrows on the two sides of the eye there are the two dhamanīs, called apāṅga, w^rhich, when hurt, produce blindness: there are also two other dhamanīs, above the eyebrows and below them, called āvarta, which, when hurt, also produce blindness. Suśruta also speaks in this connection of a place inside the skull on the upper part of the brain, where all the śirās have met together, as the adhipati superintendent.

In describing the śirās (700 in number) Suśruta says that these are like so many canals by which the body is watered and by the contraction and expansion of which the movements of the body are rendered possible. They start from the navel and branch out like so many fibres of leaves. The principal śirās are forty in number; of these ten are for the circulation of vāta, ten for pitta, ten for kapha and ten for rakta (blood). The śirās of vāta circulation again branch out into 175 śirās, and the same is the case with those which circulate pitta , kapha and rakta. We have thus altogether 700 śirās. When vāta is properly circulated through the śirās, it becomes possible for us to move our limbs without obstruction and to exercise our intellectual functions. But it should be noted that, though some śirās are regarded as mainly circulating vāyu or pitta or kapha, yet they all, at least to some extent, circulate all three^[27].

There are 900 snāyus, and these have also holes within them (suṣirāḥ), and these, as well as the kaṇḍarās, which are also but special kinds of snāyus, serve to bind the joints of the body, just as the several pieces of planks are held together in a boat. Suśruta also mentions five hundred muscles. The marmas are vital spots in flesh, śirā, snāyu and bones which are particularly the seats of prāṇa: when persons are hurt in these places, they may either lose their lives or suffer various kinds of deformity. The srotas are again described by Suśruta as being ducts, other than śirā and dhamanī, which start from the cavity of the heart and spread out through the body^[28].

These srotas carry the currents of

• prāṇa,
• food-juice,
• water,
• blood,
• flesh,
• fat,
• urine,
• excreta,
• semen
• and menstrual blood.

The Nervous System of the Tantras.

The nerve system of the Tantras, however, is entirely different from that of the medical systems of Caraka and Suśruta. It starts with the conception of the spinal column (meru-daṇḍa), which is regarded as one bone from the bottom of the back to the root of the neck. In the passage inside this spinal column there is a nerve (nāḍī), called suṣumṇā, which is again in reality made up of three nāḍīs, suṣumṇā, vajrā and citriṇī^[29]. All nāḍīs start from the root at the end of the vertebral column, called kāṇḍa, and they proceed upwards to the highest cerebral nerve-plexus, called sahasrāra, and are seventy-two thousand in number. The place of the root of these nāḍīs (kāṇḍa) is an inch above the anus and an inch below the root of the penis. If suṣumṇā is the central nerve of the spinal cord, then on its extreme right side is the iḍā, and then parallel to it towards the suṣumṇā are the gāndhārī, stretching from the corner of the left eye to the left leg, hasti-jihvā, stretching from the left eye to the left foot, śaṅkhinī, branching on the left, kuhū (the pubic nerve on the left) and also the viśvodarā, the lumbar nerves.

On the extreme left of it is th epiṅgalā, and between it and the suṣumṇā are the pūṣā, stretching from below the corner of the right eye to the abdomen, paśyantī, the auricular branch or the cervical plexus, sarasvatī and vāraṇā (the sacral nerve). The śaṅkhinī (the auricular branch or the cervical plexus on the left) goes parallel to the suṣumṇā, but takes a turn in the region of the neck and passes on to the root of the left ear-holes; in another branch it passes through the inner side of the region of the forehead, where it gets joined with the citriṇī nāḍī and enters into the cerebral region.

The suṣumṇā nāḍī is a sort of duct inside the spine, which encases within it the vajrā nāḍī, and that again encases within it the citriṇī nāḍī, which has within it a fine aperture running all through it, which is the fine aperture running through the spinal cord^[30]. This inner passage within the citriṇī nāḍī is also called brahma-nāḍī ; for there is no further duct or nāḍī within the citriṇī^[31]. The suṣumṇā thus in all probability stands for our spinal cord. The suṣumṇā, however, is said to take a turn and get connected with the śaṅkhinī in the inside region of the forehead, whence it becomes connected with the aperture of the śaṅkhinī (śaṅkkinī-nālam ālambya) and passes to the cerebral region. All the nāḍīs are connected with the suṣumṇā.

Kuṇḍalinī is a name for supreme bodily energy, and, because the channel of the suṣumṇā, the brahma-nāḍī , is the passage through which this energy flows from the lower part of the trunk to the regions of the nerve-plexus of the brain, suṣumṇā is sometimes called kuṇḍalinī ; but kuṇḍalinī itself cannot be called a nerve, and it is distinctly wrong to call it the vagus nerve, as Mr Rele does^[32]. The iḍā nāḍī on the left side of the suṣumṇā outside the spine goes upwards to the nasal region, and piṅgalā follows a corresponding course on the right side. Other accounts of these nāḍīs hold that the iḍā proceeds from the right testicle and the piṅgalā from the left testicle and passes on to the left and the right of the suṣumṇā in a bent form (dhanur-ākōre). The three, however, meet at the root of the penis, which is thus regarded as the junction of the three rivers, as it were (triveṇī), viz. of suṣumṇā (compared to the river Gaṅgā), iḍā (compared to Yāmuna) and piṅgalā (compared to Sarasvatī).

The two nāḍīs, iḍā and piṅgalā, are also described as being like the moon and the sun respectively, and suṣumṇā as fire^[33]. In addition to these nāḍīs the Yogi-yājñavalkya mentions the name of another nāḍī, called alambuṣā, making the number of the important nāḍīs fourteen, including suṣumṇā and counting suṣumṇā as one nāḍī (i.e. including vajrā and citriṇī), though the total number of nāḍīs is regarded as being seventy-two thousand. Śrīkaṇāda in his Nāḍī-vijñāna counts the number of nāḍīs as thirty-five millions. But, while the Tantra school, as represented in the works Sat-cakra-nirūpaṇa, Jñāna-saṃkalinī, Yogi-yājñavalkya, etc., regards the nāḍīs as originating from the nerve-plexus lying between the root of the penis and the anus, and while Caraka regards them as originating from the heart, Śrīkaṇāda regards them as originating from the region of the navel (nābhi-kanda) and going upwards, downwards and sideways from there.

Śrīkaṇāda, however, compromises with the Tantra school by holding that of these thirty-five millions there are seventy-two thousand nāḍīs which may be regarded as gross and are also called dhamanīs, and which carry the sense-qualities of colour, taste, odour, touch and sound (pañcendriya-guṇāvahā). There are again seven hundred nāḍīs with fine apertures, which carry food-juice by which the body is nourished. Of these again there are twenty-four which are more prominent.

The most important feature of the Tantra school of anatomy is its theory of nerve-plexuses (cakra). Of these the first is the ādhāra-cakra , generally translated as sacro-coccygeal plexus. This plexus is situated between the penis and the anus, and there are eight elevations on it. It is in touch with the mouth of the suṣumṇā. In the centre of the plexus there is an elevation called svayaṃbhū-liṅga , like a fine bud with an aperture at its mouth. There is a fine thread-like fibre, spiral in its form, attached to the aperture of the svayaṃbhū-liṅga on one side and the mouth of the suṣumṇā on the other. This spiral and coiled fibre is called kula-kuṇḍalinī ; for it is by the potential mother-energy, as manifested in its movement of a downward pressure of the apāna vāyu and an upward pressure of the prāṇa vāyu , that exhalation and inhalation are made possible and life functions operate. Next comes the svādhiṣṭhāna-cakra , the sacral plexus, near the root of the penis. Next comes the lumbar plexus (maṇi-pura-cakra), in the region of the navel. Next is the cardiac plexus (anāhata-cakra or viśuddha-cakra), in the heart, of twelve branches.

Next is the laryngeal and pharyngeal plexus, at the junction of the spinal cord and the medulla oblongata, called the bhāratī-sthāna. Next comes the lalanā-cakra , opposite the uvula. Next to this is the ājñā-cakra between the eyebrows, within which is the manaś-cakra , the centre of all sense-knowledge and dream-knowledge, and the seat of manas , the mind-organ. Vijñānabhikṣu says in his Yoga-vārttika that one branch of the suṣumṇā goes upwards from here, which is the nāḍī for carrying the functions of manas and is called mano-vahā nāḍī; the Jñāna-sarnkalinī tantra calls it jñāna-nāḍī. It seems, therefore, that it is through this nāḍī that connection is established between the soul, residing in the brain, and the manas , residing in the manaś-cakra.

Śaṅkara Miśra argues in his commentary on the Vaiśeṣika-sūtras , v. 2. 14 and 15, that the nāḍīs are themselves capable of producing tactile impressions; for, had it not been so, then eating and drinking, as associated with their corresponding feelings, would not have been possible, as these are effected by the automatic functions of prāṇa^[34]. Above the ājñā-cakra comes the soma-cakra, in the middle of the cerebrum, and finally, in the upper cerebrum, there is the sahasrāra-cakra , the seat of the soul.

The process of Yoga consists in rousing the potential energy located in the ādhāra-cakra , carrying it upwards through the aperture of the citriṇī or the brahma-nāḍī , and bringing it to the brahma-randhra or the sahasrāra. This kuṇḍalinī is described as a fine fibre like a lightning flash (taḍid iva vilasat tantu-rūpa-svarūpa), which raises the question whether this is actually a physical nerve or merely a potential energy that is to be carried upwards to the upper cerebrum in the sahasrāra-cakra ; and it cannot, I think, be yet satisfactorily explained. But, judging from a wide comparison of the texts, it seems pretty certain that it is the kuṇḍalī śakti or the kuṇḍalī energy which is carried upwards. If the kuṇḍalī energy is inexhaustible in its nature, the whole discussion as to whether the ādhāra-cakra is depleted or not or whether the kuṇḍalinī herself rises or her eject, as raised in Sir John’s Serpent Power , pp. 301-320, loses its point.

How far the cakras can themselves be called nerve-plexuses is very doubtful, since the nerve-plexuses are all outside the spinal aperture; but, if the kuṇḍalinī is to pass through the aperture of the citriṇī nāḍī and at the same time pass through the cakras , the cakras or the lotuses (padma) must be inside the spinal cord. But, supposing that these nerve-plexuses represent the corresponding places of the cakras inside the spinal cord, and also because it has become customary to refer to the cakras as plexuses, I have ventured to refer to the cakras as such. But it must be borne in mind that, as the kuṇḍalinī is a mysterious power, so also are the cakras the mysterious centres in the path of the ascent of the kuṇḍalinī. A nerve-physical interpretation of them as nerve-plexuses would be very unfaithful to the texts.

A more detailed discussion on these subjects will be found in the treatment of Tantra philosophy in a later volume of this work. The chief interest of the present section is only to show that the Tantra anatomy is entirely different in its conception from the Āyurveda anatomy, which has been the subject of our present enquiry. Another fact of importance also emerges from these considerations, namely, that, though in Dṛḍhabala’s supplementary part of the Siddhi-sthānathe head is associated with sensory consciousness, Caraka’s own part refers to the heart as the central seat of the soul. But the Tantra school points to the upper cerebrum as the seat of the soul and regards the spinal cord and its lower end as being of supreme importance for the vital functions of the body.

Footnotes and references:

[1]:

śataṃ hirāḥ sahasraṃ dhamanīr uta.
      Atharva- Veda, vii. 36. 2.

Sāyana explains hirā as garbha-dhāraṇārthaṃ antar-avasthitāḥ sūkṣmā nāḍyaḥ and dhamanī as garbhāśayasya avaṣṭambhikā sthūlā nāḍyaḥ.
      Atharva-Veda, 1. 17.

1, 2, also seems to distinguish hirā from dhamanī.

In I. 17. 1 the hirās are described as being of red garments (lohita-vāsasaḥ), which Sāyana explains as lohitasya rudhirasya nivāsa-bhūtā hi (the abode of blood) and paraphrases as rajo-vahana-nāḍyaḥ. It seems, therefore, that the larger ducts were called dhamanis.

In I. 17. 3 the Atharva-Veda speaks of huṇḍreds of dhamanīs and thousands of hirās.

[2]:

Bṛh. iv. 3. 20, with Śaṅkara’s commentary. Anandagiri, in commenting on the same, quotes a passage from Suśruta which is substantially the same as Suśruta-saṃhitā, III. 7. 18, to show that those śirās which carry vāta are rosy (aruṇa), those which carry pitta are blue, those which carry blood are red, and those which carry śleṣman are white:

aruṇāḥ śirā vāta-vahā nīlāḥ pitta-vahāḥ śirāḥ
asṛg-vahās tu rohiṇyo gauryaḥ śleṣma-vahāh śirāḥ.

[3]:

This passage is sometimes referred to in later literature to show that the suṣumṇā nāḍī, which goes towards the head, was known as early as the Chāndogya Upaniṣad. See also Kaṭha, vi. 16.

[4]:

Urdhva-gā nāḍī suṣumṇākhyā prāṇa-saṃcāriṇī.
      Maitrī, vi. 21.

Sāyana, in his commentary on A.V. 1. 17. 3, quotes the following verse:

madhya-sthāyāḥ suṣuniṇāyāḥ parva-poñcaka-saiiibhavāḥ śākhopaśākhatāṃ prāptāḥ śirā lakṣa-trayāt paraṃ ardha-lakṣam iti prāhuḥ śarīrārtha-vicārakāḥ.

[5]:

Macdonell makes the following remarks in his Vedic Index, vol. I, p. 433: “Naḍa is found in several passages of the Ṛg-Veda (1. 32, 8; 179, 4; 11. 34, 3; viii. 69, 2; x. ir, 2; 105, 4) but its sense is still obscure. It is identified by Pischel (Zeitschrift der Deutschen Morgenlandischen GeseUschaft, 35, 717 et seq.; Vedische Studien, 1. 183 et seq.) with Naḍa, being explained by him in one passage (1. 32. 8). Here Caland and Henry, L’Agniṣṭoma, p. 313 would read nalam. See also Wackernagel, Altindische Grammatik, 1. 173, as a reed boat, which is split, and over which the waters go, etc.”

[6]:

yathā naḍaṃ kaśipune striyo bhindanty aśmanā (Atharva- Veda, VI . 138. 5).

[7]:

In the Atharva-Veda, vi. 138. 4, the nāḍīs are described as ducts over the testes, through which the seminal fluid flows: ye te tiāḍyau deva-kṛte yayos tiṣṭhati vṛṣṇyaṃ te te bhinadmi (I break with a stone upon a stone those two ducts of yours made by God over your two testes, through which your semen flows). In x. 7. 15 and 16, the hollows of the seas are described as nāḍīs (samudro yasya nāḍyaḥ), and so also the interspace of the quarters of the sky (yasya catasraḥ pradiśo nāḍyaḥ).

[8]:

“Dhamanī, ‘reed,’ appears to denote ‘pipe’ in a passage of the Ṛg-Veda (11. 11. 8) and in a citation appearing in the Nirukta (vi. 24).”

      Vedic Index, vol. 1, p. 390.

The word śirā is spelt with a palatal “ś” in Caraka and with a dental in the Vedas, and it has therefore been differently spelt in this chapter in different contexts.

[9]:

tvani vṛtram āśayānaṃ sirāsu moho vajreṇa siṣvapaḥ.
      R.V. I. 121. 11.

The word dtumianī is spelt with a long “ī” in Caraka and with a short “i” in the Atharva- Veda.

[10]:

dhmānāḍ dḥamanyaḥ sravaṇāt srotāṃsi saraṇāt śirāḥ. Caraka-saṃhitā, I. 30. 11.

[11]:

Ibid. III. 5. 3.

[12]:

Doṣāṇāṃ tu sarva-śarīra-caratvena yathā-sthūla-sroto ’bhidhāne ’pi sarva-srotāṃsy eva gamanārthaṃ vakṣyante. .. vātādīnām api pradhāna bhūtādhamanyaḥ santy eva.
      Cakrapāṇi’s comment on ibid.

[13]:

āhāra-pariṇāma-raso hi srotasāṃ chidra-rūpaṃ panthānaṃ vinā gantuṃ na śaknoti, na ca srotaś chidra-pathena gamanaṃ vinā tad-uttarottara-dhātutvena pariṇamati, etc.
      Gaṅgādhara’s Jalpa-kalpa-taru on ibid.

[14]:

Gaṅgādhara, in commenting on this passage (Caraka-saṃhitā, III. 5. 7),

“tadvad atīndriyāṇāṃ punaḥ sattvādīnāṃ kevalaṃ cetanāvac chafīram ayana-bḥñ-tam adhiṣṭhāna-bhūtaṃ ca,”

says,

“mana ātmā śrotra-sparśana-nayana-rasana-ghrāṇa-huddhy-ahaṅkārādināṃ kevalam cetanāvat sajīvaṃ śarīra-sroto ’ yana-bhūtani adhiṣṭhāna-bhūtaṃ ca”

There are several passages in Caraka where we hear of mano-vaha currents (currents carrying manas); if manas, buddhi, ahaṅkāra, etc. can all be carried in currents, they must be considered as having some material spatial existence. These manas, buddhi and ahaṅkāra may be atīndriya, but they are not on that account non-physical.

[15]:

Caraka-saṃhitā, iii. 5. 10. Cakrapāṇi explains it {kloma) as hṛdaya-stham pipāsā-sthānam, and Gaṅgādhara as the point of conjunction between the throat and the heart (kaitṭhorasoḥ sandhill).

[16]:

The synonyms for srotas given by Caraka are śirā, dhamanī, rasa-vāhinī, nāḍī, panthā, mārga, śarīra-chidra, saṃvṛtāsaṃvṛtāni (open at the root, but closed at the end), sthāna, āśaya and niketa.

[17]:

There is one passage of Drḍhabala {Caraka-saṃhitā, vi. 29. 23) which seems to draw a distinction between śirās and dhamanīs", for there, as a symptom of a disease, it is said that the śirās have expanded (āyāma) and the dhamanīs have become contracted (saṅkoca).

[18]:

na ca Carake Suśruta iva dhamanī-śirā-srotasāṃ bhedo vivakṣitaḥ.
      Cakrapāṇi’s commentary on Caraka, iii. 5. 3.

[19]:

Suśruta-saṃhitā, in. 7. 8-17.

[20]:

Ḍalhaṇa on ibid. iii. 9. 3.

[21]:

Ibid.

[22]:

Thus Ḍalhaṇa remarks:

ākāśīyāvakāśānāṃ dehe nāmāni dehināṃ
śirāḥ srotāṃsi mōrgāḥ khaṃ dhamanyaḥ.

[23]:

Suśruta , Śārīra , IX. 7 and 8; see also Ḍalhaṇa’s commentary on it. The apertures of some dhamanis by which the food-juice is circulated through the body are as fine as lotus fibres, and some grosser than them, as the apertures of lotus stalks.

Thus some dhamanīs have very fine apertures, and others grosser apertures.

yathā svabhāvataḥ khāni mṛṇāleṣu biseṣu ca
dhamanīnāṃ tathā khāni raso yair upacīyate.
      Ibid. ix. 10.

[24]:

Suśruta, Śārīra, ix. 7 and 8; see also Dalhana’s commentary on it.

[25]:

Dalhana, in commenting on this passage of Suśruta, 111. ix. 9, says:

“tair eva mano-nugataiḥ sukḥāsukha-rūpaṃ sparśaṃ karmātmā gṛhṇīte”

(It is through these dhamanīs, as connected by manas, that the self, as associated with the subtle body, receives the pleasurable and painful impressions of touch.)

[26]:

pañcābhibhūtās tv atha pañca-kṛtvaḥ
pañcendriyaṃ pañcasu bhāvayanti
pañcendriyaṃ pañcasu bhāvayitvā
pañcatvam āyānti vināśa-kāle.
      Suśruta, 111. ix. 11.

Dalhana, in commenting on the above, says:

“mantā hi śarīre eka eva, mano ’py ekam eva, tena manasā yaiva dhamanī śabdādi-vahāsu dhamamṣv abhiprapannā saiva dhamanī sva-dharmaṃ grāhayati mantāraṃ nānyeti.”

[27]:

na hi vātaṃ śirāḥ kāscin na pittaṃ kevalaṃ tathā
śleṣmānam vā vaḥanty etā ataḥ sarvavaḥāḥ smṛtāḥ.
      Suśruta, ill. vii. 16.

[28]:

mūlāt kḥād antaraṃ deḥe prasṛtaṃ tv abhivāḥi yat
srotas tad iti vijñeyaṃ śirā-dḥamatñ-varjitam.
      Suśruta, Śārīra, ix. 13:

[29]:

But according to the Tanira-cūḍāmaṇi, suṣumṇā is not inside the spinal column but outside it. Thus it says,

“tad-bāḥye tu tayor madhye suṣumṇā vahni-saṃyuta .”

This, however, is against the view of the Saṭ-cakra-nirūpaṇa , which takes suṣumṇā to be inside the passage of the spine. According to the Nigama-tattva-sāra-tantra, iḍā and piñgalā are both inside the spine, but this isenti rely against the accepted view. Dr Sir B. N. Seal thinks that suṣumṇā is the central passage or channel of the spinal cord and not a separate nāḍī (The Positive Sciences of the Ancient Hindus, pp. 219, 226, 227).

Mr Rele in his The Mysterious Kuṇḍalitñ (pp. 3 5,3 6) thinks that it is a nāḍī which is situated centrally and passes through the spinal column (meru-daṇḍa); but, judging from the fact that it is said to originate in the sacrum, from which it goes upwards to the base of the skull, where it joins with the plexus of a thousand nerves called brahma-cakra (cerebrum in the vault of the skull) and is divided at the level of the larynx (kaṇṭha) into anterior and posterior parts between the two eyebrows (ājñā-cakra) and the cavity in the brain (brahma-randhra) respectively, Rele thinks that this suṣumṇā nāḍī is nothing but the spinal cord.

[30]:

Nāḍī is derived by Pūrnānanda Y ati, in his commentary on the Saṭ-cakra-nirūpaṇa, from the root naḍ, to go, as a passage or duct (naḍa gatau iti dhātor naḍyate gamy ate ’nayā padavyā iti nāḍī). Mahāmahopādhyāya Gananātha Sen makes a very serious mistake in his Pratyakṣa-śārīraka when he thinks that the nāḍīs are to be regarded as being without apertures (nīrandḥra). They are certainly not so regarded in the Āyurveda or in the Saṭ-cakra-nirūpaṇa and its commentaries. In Yoga and Tantra literature the term nāḍī generally supersedes the term śirā of the medical literature.

[31]:

Śabda-brahma-rūpāyaḥ kuṇḍalinyāḥ parama-śiva-sannidḥi-gamana-patḥa nipa-citriṇī-nāḍy-antargata-śūnya-bhāga iti.
      Pūrnānanda’s commentary on Saṭ-cakra-nirūpaṇa, St. 2.

[32]:

Suṣumṇāyai kuṇḍalinyai.
      Haṭḥa-yoga-pradīpikā, IV. 64.

[33]:

Saṭ-cakra-nirūpaṇa, St. 1 and Yogi-yājñavalkya-saṃḥitā, p. 18.

[34]:

See Dr Sir B. N. Seal’s Positive Sciences of the Ancient Hindus , pp. 222-225.