（灵枢平人绝谷篇 全）
黄帝曰∶愿闻人之不食，七日而死何也？伯高曰∶臣请言其故。
胃大一尺五寸，径五寸，长二尺六寸，横屈受水谷三斗五升。其中之谷常留二斗，水一斗五升而满。上焦泄气，出
其精微 悍滑疾，下焦下溉诸肠。（精微 悍滑疾，言水谷之质粕也。）
小肠大二寸半，径八分分之少半，长三丈二尺，受谷二斗四分，水六升三合合之大半。
回肠大四寸，径一寸寸之少半，长二丈一尺，受谷一斗，水七升半。
广肠大八寸，径二寸寸之大半，长二尺八寸，受谷九升三合八分合之一。
肠胃之长，凡五丈八尺四寸，受水谷九斗二升一合合之大半，此肠胃所受水谷之数也。（五丈八尺四寸，乃止合肠胃
之数，非若前篇总计唇口咽门而言也。）平人则不然，胃满则肠虚，肠满则胃虚，更虚更满，故气得上下，五脏安定，血
脉和利，精神乃居，故神者水谷之精气也。（上文云受水谷九斗二升一合合之大半者，乃言肠胃能容之总数也。若平人常
数，则不皆然。盖胃中满则肠中虚，肠中满则胃中虚，有满有虚，则上下之气得以通达，五脏血脉得以和调，而精神乃
生，故神为水谷之精气也。）故肠胃之中，常留谷二斗，水一斗五升。故平人日再后，后二升半，一日中五升，七日五七
三斗五升，而留水谷尽矣。故平人不食饮，七日而死者，水谷精气津液皆尽故也。（平人肠胃之中，所存水谷，惟三斗五
升而已；然人之二便，大约日去五升，当七日而尽，故平人不食饮七日而死也。古今量数不同，详见附翼二卷。）
Ling Shu: Ping Ren Jue Gu Chapter (Full Text)
Huang Di said: I wish to hear why a person dies after seven days without food. Bo Gao said: Please allow me to explain the reason.
The stomach has a capacity of one chi five cun, a diameter of five cun, and a length of two chi six cun; its curved portion can hold three dou five sheng of water and grain. Under normal conditions, it retains two dou of grain and one dou five sheng of water when full. The Upper Jiao (Upper Burner, responsible for dispersing Qi and fluids) releases Qi, expelling the essence, vigorous nature, smoothness, and rapid movement [of nutrients]; the Lower Jiao (Lower Burner, responsible for separating clear from turbid and excreting waste) irrigates downward into the various intestines. ([The terms "essence, vigorous nature, smoothness, and rapid movement" refer to the quality of the residue of water and grain.])
The small intestine has a diameter of two cun half, a radial measurement of eight fen plus a minor fraction, and a length of three zhang two chi; it can hold two dou four sheng of grain and six sheng three he plus a major fraction of a he of water.
The returning intestine (Hui Chang) has a diameter of four cun, a radial measurement of one cun plus a minor fraction, and a length of two zhang one chi; it can hold one dou of grain and seven sheng half of water.
The broad intestine (Guang Chang) has a diameter of eight cun, a radial measurement of two cun plus a major fraction, and a length of two chi eight cun; it can hold nine sheng three he plus one-eighth of a he of grain.
The total length of the gastrointestinal tract is five zhang eight chi four cun, capable of holding nine dou two sheng one he plus a major fraction of a he of water and grain; this is the quantity of water and grain that the gastrointestinal tract can contain. ([Five zhang eight chi four cun refers only to the number of units comprising the gastrointestinal tract itself, not including the lips, mouth, and pharynx as mentioned in the previous chapter.]) A healthy person is different: when the stomach is full, the intestines are empty; when the intestines are full, the stomach is empty. Through this alternating emptiness and fullness, Qi circulates up and down, the Five Zang Organs remain stable, the blood vessels are harmonious and unobstructed, and Spirit resides therein. Therefore, Spirit is the essential Qi derived from water and grain. ([The statement above regarding the capacity of nine dou two sheng one he plus a major fraction refers to the total volume the gastrointestinal tract can hold. In a healthy person's daily state, this is not always the case. Because when the stomach is full, the intestines are empty, and when the intestines are full, the stomach is empty, the Qi of the upper and lower parts can communicate freely, the blood vessels of the Five Zang Organs can harmonize, and Spirit arises. Thus, Spirit is the essential Qi of water and grain.]) Consequently, within the gastrointestinal tract, there are usually two dou of grain and one dou five sheng of water retained. Therefore, a healthy person defecates twice a day, with each bowel movement being two sheng and half, totaling five sheng per day. Over seven days, this amounts to five times seven, which is three dou five sheng, exhausting the retained water and grain. Hence, a healthy person who does not eat or drink will die after seven days because the water, grain, essential Qi, and Jin-Ye (Body Fluids) are all exhausted. ([The amount of water and grain stored in the gastrointestinal tract of a healthy person is only three dou five sheng; however, human excretion via urine and feces is approximately five sheng per day. By the seventh day, it is completely exhausted. Thus, a healthy person dies after seven days without food or drink. Measurement standards differ between ancient and modern times; see Volume 2 of the Appendix for details.])