This section is from the book "The Beverages of the Chinese; Kung-fu or Tauist Medical Gymnastics; the Population of China; A Modern Chinese Anatomist and A Chapter in Chinese Surgery.", by John Dudgeon. Also available from Amazon: Kung Fu, or Taoist Medical Gymnastics.
The idea of kneading is rubbing or shampooing the sinews and bones strong. It consists of three portions, each of 100 days.
(1). - Kneading in season. Beginning in spring when the weather is still a little cold and the body is closely wrapped up in clothes, it is only necessary to open the upper clothes. In the middle of the second month when the weather has grown warmer, the lower part of the body may then be exercised and thereafter one may practise most conveniently.
(2). - Certain forms of kneading. Man's animal vigour (air) is situated on the right side of the body and the blood on the left. In kneading one must begin and advance from the right to the left. The raison d'etre are three. (1). - To push the vigour so that it enters the blood and makes them mix. (2). - To broaden the stomach so that it may receive more vigour. The stomach is situated on the right side. (3). - The right palm of the kneader is more powerful than the left.
(3). - The quality of the kneading. It must be light and superficial. The process, although the individual's, ought to be in accordance with heaven's laws and with the production of things by heaven and earth; slowly, little by little and not suddenly. When the air arrives it necessarily causes growth; then wait till it is complete, kneading ought to be done after this fashion, the pushing ought to be even and uniform, slowly coming and going backwards and forwards; not too heavy and not too deep. When one has exercised for a long time, then one obtains the advantages, this is the proper thing; if too heavy, the skin may get injured and perhaps set up disease (such as pityriasis versicolor and lichen tropicus); if deep the muscles, sinews and membranes may inflame and swell, hence the necessity of care.