Recently, the University of Southern California released the results of a multi-year study on the common cold. The researchers said their findings showed that the most effective means of preventing the common clod was a five thousand year old yoga technique — irrigating the nose. As well as cleaning the sinuses and nasal passages, the technique was credited by the study with boosting the immune system. This simple daily procedure is demonstrated in detail with illustrations on pages 116 and 117 of the yoga manual: Weight Loss Through Yoga, Jewel in the Lotus.