Kung-Fu, or Tauist Medical Gymnastics, by John Dudgeon, , at sacred-texts.com
It will be observed that the cause of disease is invariably supposed to depend upon the presence of vitiated or depraved air having stealthily gained admittance. The air thus shut up causes obstruction. It is sometimes termed thievish or air deflected from its proper course. The Chinese proverb runs, avoid a draught of air as you would the point of an arrow.—It is recommended to rub the soles of the feet until hot and also to move each toe; this
measure being effectual in preserving and repairing the vital and animal spirits. The middle of the sole of the foot is supposed to be the outlet of a great many services of spirits and like mouths of rivers, the arteries and veins end there and therefore must be kept open.—It is advisable every time one awakes, to stretch one's self in bed, thus facilitating the course of the spirits and circulation. One ought not to sleep like a dead man (i.e., not to lie on one's back), nor to let the hands rest on the breast or heart, so as to avoid dreams and nightmares. Once in bed to keep silence, to refrain from talking; the lungs are the most tender of the viscera and consequently placed uppermost and they serve for respiration and promotion of the voice. On taking any position in bed, they incline to rest upon that side; by talking the lungs are forced to raise themselves in part and by strongly heaving; shake the other noble internal parts. The voice comes from the lungs as the sound from a bell, if the bell be not hung, it is damaged by striking it to make it sound. Confucius never spoke after he was in bed; he made it a rule doubtless for this reason. The Chinese have as a rule good teeth. The better classes use warm tea or water with which to cleanse them each morning and after meals. It is ordered to sleep with the head and face uncovered and with the mouth shut as it tends to keep the radical moisture from escaping and preserves the teeth. Early loss of teeth is caused by the air passing in and out between them; besides gross particles are inhaled which give rise to distempers.
The tan-t‘ien is situated about 1½ inches below the navel and is brought into exercise with the bow and arrow exercise. A man is said to be strong when this is in sufficient quantity.