Raja Yoga (the Yoga Sūtras with commentary) — trans. Swami Vivekananda (1896)

this Prana these various vital forces. First of all the forces that keep the body in preservation, and lastly thought, will, and all other powers. By this process of breathing we can control all the various motions in the body, and the various nerve currents that are running through the body. First we begin to recognise them, and then we slowly get control over them. Now these later Yogis consider that there are three main currents of this Prana in the human body. One they call Idii, another Pingala, and the third Susumna. Pingala, according to them, is on the right side of the spinal column, and the Ida is on the left side, and in the middle of this spinal column is the Susumna, a vacant channel. Ida and Pingala, according to them, are the currents working in every man, and through these currents, we are performing all the functions of life. Susumna is present in all, as a possibility ; but it works only in the Yogi. You must remember that the Yogi changes his body ; as you go on practising your body changes ; it is not the same body tliat you had before the practice. That is very rational, and can be explained, because every new thought that we have must make, as it were, a new channel through the brain, and that explains the tremendous conservatism of human nature. Human nature likes to run through the ruts that are already there, because it is easy. If we think, just for example's sake, that the mind is like a needle, and the brain substance a soft lump before it, then each thought that we have makes a street, as it were, in the brain, and this

YOGA APHORISMS.

street would close up, but that the grey matter comes and makes a lining to keep it separate. If there were no grey matter there would be no memory, because memory means going over these old streets, retracing a thought as it were. Now perhaps you have remarked that when I talk on subjects in which I take a few ideas that are familiar to everyone, and combine, and recombine them, it is easy to follow, because these channels are present in everyone's brain, and it is only necessary to recur to them. But whenever a new subject comes new channels have to be made, so it is not understood so readily. And that is why the brain (it is the brain, and not the people themselves) refuses unconsciously to be acted upon by new ideas. It resists. The Prana is trying to make new channels, and the brain will not allow it. This is the secret of conservatism. The less channels there have been in the brain, and the less the needle of the Prana has made these passages, the more conservative will be the brain, the more it will struggle against new thoughts. The more thoughtful the man, the more complicated will be the streets in his brain, and the more easily he will take to new ideas, and understand them. So with every fresh idea ; we make a new impression in the brain, cut new channels through the brain-stuff, and that is why we find that in the practice of Yoga (it being an entirely new set of thoughts and motives) there is so much physical resistance at first. That is why we find that the part of religion which deals with the world side of nature can be so widely accepted, while the