Three Ancient Qigong practitioners on breathing

The following excerpt is from the book Qi Gong Therapy: The Chinese Art of Healing With Energy by Tzu Kuo Shih, Station Hill Press, Barrytown NY, 1994.

P. 14-15:

Sun Simiao [AD 581-682] was a renowned physician and Daoist of the Tang Dynasty [AD 618-907]. There are many descriptions of Qi Gong practices in his works, Essential Prescriptions Worth a Thousand in Gold (Qian Jin Fang) and Supplement to the Prescriptions Worth a Thousand in Gold (Qian Jin Yi Fang). In the chapter, "Methods of Breath-Regulation" he details four methods: abdominal breathing, internal seeing, breath controlling, and exhalation. The four methods are the essence of ancient Chinese Qi Gong.

In his Song for Eliminating Diseases in the Four Seasons (Si Ji Qu Bing Ge), Dr. Sun wrote:

Exhaling with mouth not open can improve the sight and soothe the liver in spring. Exhaling with the mouth open wide, in spring, can clear away the heart-fire. Exhaling with the mouth open but teeth clenched in autumn, can astringe the lung and relieve cough and asthma. Exhaling can reinforce the kidney. Producing the sound "shee—" can eliminate restlessness and fever of deficiency type of San-jiao [triple burner]. Rapid exhalation can reinforce the spleen and promote digestion.

Wang Shou was another famous Qi Gong practitioner from the Tang Dynasty. In his work, The Medical Secrets of an Official (Wai Tai Mi Yao) he says:

The method to treat diseases of the heart and abdomen and all other diseases is through breathing.

P. 22-23:

Gong Yan Xian was a doctor of the Imperial hospital during the Min Dynasty. [Min Dynasty: AD 909-946] He wrote Living a Long Life and Preserving Fundamental Energy (Shou Shi Bao Yuan) which discoursed upon breathing and standing Qi Gong. He wrote:

It is said a person's life is based on energy. When the breath occurs between the heart and the spleen, then the blood flows smoothly, the vitality is strengthened, and all diseases disappear. At midnight, noon, dawn, and dusk, stay in your room quietly, the bed fitted with a heavy cotton-padded mattress, and sit on the bed with legs crossed, closing your eyes and filling your ears with cotton, not thinking anything—take your breath between your heart and spleen, not too fast and not too slow. Just take it easy. When you practice this for two months, you will get Qi Gong results.