These Yogins by persistent effort in concentration get different Yogic powers that are known as 'Siddhis'. Those who acquire these Siddhis, are known as Siddhas. The process through which they obtain Siddhis is called Sadhana. Pranayama is one of the most important Sadhanas. Through the practice of Asana, you can control the physical body and through Pranayama, you can control the subtle, astral body or the Linga Sarira. As there is an intimate connection between the breath and nerve-currents, control of breath leads to the control of vital inner currents.

Pranayama occupies a very important place in Indian religion. Every Brahmachari, and every Grihastha also, has to practise it three times every day morning, noon and evening in his daily worship during Sandhya. It precedes every religious practice of the Hindus. Before he eats, before he drinks, before he resolves to do anything, Pranayama should be performed first and then the nature of his determination should be clearly enunciated and placed before the mind. The facts of its preceding every effort of the will is a surety that, that effort will be crowned with success and the mind will be directed to bring about the desired result. Here I may refer to the feat of memory, practised by the Hindu Yogins, under the name of concentration on one hundred things, 'Satavadhana', wherein one hundred questions are put to a Satavadhani or the concentrator in rapid succession by different persons, some testing the verbal memory of the performer, others testing his power of mental calculation, again some others, trying to test his artistic skill, without giving him any time for committing to memory the questions put to him. The performer begins by reproducing the questions, in any order, in respect of those questions, with their answers. This is generally done in three or more turns, in each turn giving only a portion of the answer to each of the questions and then continuing from where he left off in the next turn. If the questions are of the nature of mathematical problems whose solutions are required, he delivers the answers along with the problems, having solved them mentally.

This faculty of concentration of mind is often exhibited not only with reference to the intellect but also with reference to the five senses. A number of bells may be marked differently and the sounds may be allowed to be studied and made mental note of with the mark given to it. A number of objects of similar shape and colour which are likely to cause deception to the eye of an ordinary man may be shown once to the 'Avadhani' with their marks. While he is attending to other things, if a bell were to be struck or one of the objects suddenly exhibited before his sight, he will at once mention the mark of the bell or the number of the object shown. Similarly his keenness of touch is also put to the test. Such feats of memory are due to the training which they receive from the daily practice of Pranayama.

The Prana may be defined as the finest vital force in everything which becomes visible on the physical plane as motion and action, and on the mental plane as thought. The word Pranayama, therefore, means the restraint of vital energies. It is the control of vital energy which tingles through the nerves of persons. It moves his muscles and causes him to sense the external world and think his internal thought. This energy is of such a nature that it may be called the vis viva of the animal organism. The control of this force is what is aimed at by the Yogins by means of Pranayama. He who conquers this is not only the conqueror of his own existence on the physical and mental plane, but the conqueror of the whole world. For, the Prana is the very essence of cosmic life, that subtle principle which evolved the whole universe into its present form and which is pushing it towards its ultimate goal. To the Yogi the whole universe is his body. The matter which composes his body is the same that evolved the universe. The force which pulsates through his nerves is not different from the force which vibrates through the universe. The conquest over the body does, therefore, mean to him the conquest over the forces of nature. According to the Hindu Philosophy, the whole nature is composed of two principal substances. One of them is called the Akasa or ether and the other, Prana or energy. These two may be said to correspond to matter and force of the modern scientists. Everything in this universe that possesses form or that has material existence is evolved out of this omnipresent and all-pervasive subtle substance 'Akasa'. Gas, liquid and solid, the whole universe, consisting of our solar system and millions of huge systems like ours and in fact every kind of existence that may be brought under the word 'created', are the products of this one subtle and invisible Akasa and at the end of each cycle return to the starting point. In the same way, all the various forces of nature that are known to man-gravitation, light, heat, electricity, magnetism-all those that can be grouped under the generic name of 'energy', physical creation, nerve-currents, all such as are known as animal forces, and thought and other intellectual forces also, may be said to be the manifestations of the cosmic Prana. From Prana, they spring into existence, and in Prana, they finally subside. Every kind of force in this universe, physical or mental, can be resolved into this original force. There can be nothing new except these two factors in some one of their forms. Conservation of matter and conservation of energy are the two fundamental laws of nature. While one teaches that the sum total of Akasa forming the universe is constant, the other teaches that the sum total of energy that vibrates the universe is also a constant quantity. At the end of each cycle the different manifestations of energy quiet down and become potential; so also the Akasa which becomes indistinguishable; but at the beginning of the next cycle the energies start up again and act on the Akasa so as to evolve the various forms. Accordingly, when the Akasa changes and becomes gross or subtle, Prana also changes and becomes gross or subtle. As the human body is only a microcosm to a Yogi, his body composed of the nervous system and the internal organs of perception represent to him the microcosmic Akasa, the nerve-currents and thought-currents, and the cosmic Prana. To understand the secrets of their workings and to control them is, therefore, to get the highest knowledge and the conquest of the universe.

He, who has grasped this Prana, has grasped the very core of cosmic life and activity. He, who has conquered and controlled this very essence, has not only subjected his own body and mind but every other body and mind in this universe. Thus Pranayama or the control of Prana is that means by which the Yogi tries to realise in his little body the whole of cosmic life, and tries to attain perfection by getting all the powers in this universe. His various exercises and trainings are for this one end.

Why delay? Delay means so much of additional suffering and misery. Let us increase the speed, struggle harder until we succeed in bridging over the vast chasm of time. By doing proper Sadhana let us attain the goal at once in this body, right now in this very moment. Why not we get that infinite knowledge, infinite bliss, infinite peace and infinite power, now itself?

The solution of the problem is the teaching of Yoga. The whole science of 'Yoga' has this one end in view, to enable man to cross the ocean of Samsara, to increase power, to develop knowledge and to attain immortality and eternal bliss.