Prana is the essence of all life and non-life. It is the life force that is present in animal, plant and all other forms of life. Prana manifests according to the vibratory rate of the body it permeates. Cosmic prana infuses all life forms, although it may appear to be a separate entity or take a different form. In the same way that white light will emit the different colours of the spectrum as it passes through changing densities of matter, so also the cosmic prana as it passes through different densities of life forms.
There are five separate strata of existence which are contained within the form of a human being and which mutually co-exist.
They are referred to as the five sheaths (Sanskrit: kosha): annamaya kosha, pranamaya kosha, manomaya kosha, vigyammaya kosha and anandamaya kosha. These correspond to the physical, vital, mental, intuitive and blissful planes mentioned in western mysticism. The astral body refers to both manomaya and vigyanamaya kosha combined.
Just as a generator sets a machine in action, so the cosmic prana is the vitalizing factor which operates these five sheaths. Cosmic prana allows these sheaths to perform their functions continuously even in the absence of continued conscious awareness. In most human beings conscious awareness exists only on the physical plane. Awareness of the other states of existence can be developed through prana vidya.
The annamaya kosha is the physical sheath of the body. It is referred to as the food sheath due to its dependence on gross prana in the form of food, water and air. However, its existence is more dependent on subtler prana. While it is possible to go without food for up to six weeks, water for three days and air for six minutes, life ceases immediately if subtle prana is withdrawn.
The vital sheath of the body is called the pranamaya kosha, or pranic body. Together, the physical and the pranic body constitute the basic structure of man. This is sometimes referred to as atmapuri. Atma means 'soul', and puri means 'city'. Through this vital and physical body alone, self realization is possible, because it is here that the astral and causal bodies reside.
For this reason a person should learn all about the gross body: the construction, physiology and anatomy of the physical and pranic body, the eight chakras and the nine gates, all of which constitute the means of awakening. Realization can occur either through the expansion of consciousness as in jnana or raja yoga, or through control of prana as in prana vidya.
The pranic body is more subtle than the physical body which it pervades. The pranic body provides energy and infuses life into the physical body. This gross form of prana dies with the body. It is traditionally divided into five main forms, collectively known as the pancha pranas (five pranas): prana, apana, samana, udana, and vyana. These are separate manifestations of the pranamaya kosha or vital sheath and have distinct functions. Prana activates inhalation and exhalation and is associated with the respiratory and speech organs.
It is located in the region between the larynx and the top of the diaphragm. Apana is located below the navel region and activates expulsion and excretion. Samana activates and controls the digestive system: liver, intestines, pancreas, stomach, as well as the heart and circulatory system in general. It is concerned with the region between the heart and the navel and is responsible for the assimilation of nutrients. Udana activates the organs of sense, especially those located above the larynx: eyes, nose, ears, tongue and also the sensory receptors all over the body. Vyana is the vital force that regulates the overall movements of the body and coordinates the other vital energies.
The pranic body supports the life of the physical body. Neither can exist alone. The pranic body is approximately the same size and shape as the physical body. Just as the physical body receives nourishment, so also does the pranic body. The prana which sustains the pranic body is drawn from the more subtle sheaths of the manomaya, vigyanamaya and anandamaya koshas. Prana exists as light and energy in the pranamaya kosha. In its gross form it is likened to the flame of lire that flickers, waxes and wanes. The colour and shape vary. In Kirlian photography it has been revealed as small flames of energy bursting from the pores of the body in a constant ebb and flow of life force. The pranic body itself, however, is initially visualized as a smoky aura with the same shape, limbs and parts as the physical body. As the practitioner develops and gradually purifies body and mind, the pranic body takes on a golden colour which gives way finally to a luminous transparent glow.
More subtle than the pranamaya kosha is the manomaya kosha, the mental sheath. It performs many functions simultaneously and provides the cement that holds the two grosser annamaya and pranamaya koshas together as an integrated whole. It acts as a messenger between each body, conveying the experiences and sensations of the external world to the intuitive body, and the influences of the causal and intuitive bodies to the gross body. Mind is capable of attaining the greatest speed. Thought is the ultimate manifestation of motion. The mind can move forward and backward in time. Time does not exist as a barrier, and in the techniques of meditation time can be experienced as ceasing to exist. The power or energy source for attaining these abilities is prana. The mind reflects the basic nature of the universe.
Pervading and more subtle than the manomaya kosha is the vijyanamaya kosha, the sheath of intuition. When this sheath is awakened, one begins to experience life intuitively, to see deeper reasons behind all manifested things. This leads to wisdom.
Then comes the anandamaya kosha, the sheath of bliss, the final sheath of individual being. This is the causal body, the abode of the most subtle prana. It is beyond definition.
All five sheaths are pervaded by prana, whether gross or subtle. Prana is the essence of life. It nourishes and sustains all the sheaths and maintains their correct relationship.
In everything, in every human body, there is only one prana. To become aware of one's own prana is to become aware of prana in other living beings. By becoming aware of one's own prana, one connects with cosmic prana. It is in this way that pranic healing takes place. By gaining control over one's own prana, one can influence the prana of others. This can be accomplished when one's own prana is purified through yogic practices.
The practice of prana vidya results in a specific psychic experience of the direct perception of prana at different levels of subtlety in the five sheaths. One awakens prana and thereby experiences its flow, form, colour and quality.
The physical sheath, annamaya kosha, can be perceived through the physical eyes. The first stage of prana vidya is concerned with transcending awareness of the gross body by inducing pratyahara, sense withdrawal. Gradually one will become aware of the pranic sheath, pranamaya kosha. One will see prana like stars shining in the night. If one stares at the stars, he may experience a flow of tears. The stars then take on the form of a point of light surrounded by thin streaks of light shooting outward from the centre. Normally this colour is of a golden hue; at other times it may be affected by the influence of the mind. The light takes on the colour of emotions, feelings and desires. These colours vary in degree and intensity. Some clairvoyant people are able to discern the state of mind of a person merely by watching the play, intensity and degree of light and colour about him. This human aura is one gross manifestation of prana. Knowledge of this play can be gained from the practice. Then one starts to perceive the mental sheath, manomaya kosha. The subtle aspects of the mind can be visualized as the abode of light. The quality and luminosity of the light depend on the purity of the mind. Some visualize the manomaya kosha as a sheath of light having shape and form, others as light emanating cyclically from a central source.
In meditative states perception of the intuitive sheath, vigyanamaya kosha, arises. One has visions and intuitions of the essence of all things.
The last sheath to be entered is the ocean of bliss, anandamaya kosha. Here is the threshold of samadhi, the abode of paramatma, cosmic self. This sheath may appear in the form of a luminous shiva lingam, etc. Each of these symbols can be used In tantric visualization techniques as a means to totally absorb one's awareness and thereby awaken experience of the anandamaya kosha Perception of each of these five sheaths can be progressively awakened through the practice of prana vidya. When all these sheaths are transcended, one expands into the state of samadhi.