The kriyas are the techniques of internal purification of body. The most widely known kriyas are Dhauti, Neti and Basti.
Dhauti is the purification of the abdomen and stomach. This is not a matter of simply swallowing a strip of material four fingers wide and five yards long. It should first be dipped in a bowl of water and then squeezed out. Then one of the ends is put in to the mouth and swallowed inch-by-inch before being removed.
This is how cleansing of the stomach and abdomen should be performed. Many ignorant people imagine that the Yogis remove their intestine and wash them, whereas in fact they are simply carrying Dhauti.
Neti is the flushing or cleansing of the nose. There are two ways of doing this; the first is to take a bowl or glass of warm water, dip the nose in it and slowly breather in the water through the nostrils. The water will automatically trickle down in to the throat and be evacuated through the mouth.
The second is to use a string. This should be extremely soft and tightly woven, and some eight inches long. The end should be stiffened with bees wax. The string should be closed with the finger. The string should be completely immersed in water, before being put into one nostril while the other is held closed with finger.
The string is then inhaled successively in deep breaths. Once it is felt at the back of the throat, it is taken between the index finger and thumb, very gently to avoid pain, then drawn out of the mouth and moved back and forth to thoroughly cleanse the nostril. The same is done for the other nostril.
Basti is the washing of the intestines, provided one knows how to isolate the recto-abdominal muscles and open the sphincter at will. It is possible to draw water through the colon by slowly contracting the rectum. By giving the abdominal muscles a good shake, the water may be expelled immediately.
Many people are tempted to perform these various internal purification kriyas to avoid illness, rather than practicing the Asnas and Pranayama, in the belief that they will thus obtain better results. These Kriyas should be performed under the guidance of some trained person, who knows accurately how to perform them.