素问·解精微论 Discourse Explaining the Subtle and Profound
黄帝在明堂，雷公请曰：臣授业传之，行教以经论，从容形法，阴阳刺灸，汤药所滋，行治有贤不肖，未必能十全。若先言悲哀喜怒，燥湿寒暑，阴阳妇女，请问其所以然者，卑贱富贵，人之形体所从，群下通使，临事以适道术，谨闻命矣。请问有毚愚仆漏之问，不在经者，欲闻其状。帝曰：大矣。公请问：哭泣而泪不出者，若出而少涕，其故何也。帝曰：在经有也。复问：不知水所从生，涕所从出也。帝曰：若问此者，无益于治也，工之所知，道之所生也。
夫心者，五藏之专精也，目者，其窍也，华色者，其荣也，是以人有德也，则气和于目，有亡，忧知于色。是以悲哀则泣下，泣下水所由生。水宗者，积水也，积水者，至阴也，至阴者，肾之精也。宗精之水，所以不出者，是精持之也。辅之裹之，故水不行也。夫水之精为志，火之精为神，水火相感，神志俱悲，是以目之水生也。故谚言曰：心悲名曰志悲，志与心精，共凑于目也。是以俱悲则神气传于心，精上不传于志，而志独悲，故泣出也。
泣涕者，脑也，脑者，阴也，髓者，骨之充也，故脑渗为涕。志者，骨之主也，是以水流而涕从之者，其行类也。夫涕之与泣者，譬如人之兄弟，急则俱死，生则俱生，其志以早悲，是以涕泣俱出而横行也。夫人涕泣俱出而相从者，所属之类也。
雷公曰：大矣！请问人哭泣而泪不出者，若出而少涕，不从之何也？帝曰：夫泣不出者，哭不悲也；不泣者，神不慈也。神不慈则志不悲，阴阳相持，泣安能独来？夫志悲者惋，惋则冲阴，冲阴则志去目，志去则神不守精，精神去目，涕泣出也。且子独不诵不念夫经言乎？厥则目无所见，夫人厥则阳气并于上，阴气并于下。阳并于上则火烛光也，阴并于下则足寒，足寒则胀也。夫一水不胜五火，故目眦盲。是以冲风，泣下而不止。夫风之中目也，阳气内守于精，是火气燔目，故见风则泣下也。有以比之，夫火疾风生，乃能雨，此之类也。
Huangdi was in the Hall of Light. Lei Gong requested, saying: I have received this learning and transmitted it, carrying out instruction by means of the classical discourses — unhurried deliberation, the forms and models, yin and yang, needling and moxibustion, and what is nourished by decoctions and medicines. Yet in carrying out treatment there is skill and lack of skill, and one cannot always be certain of complete success in ten cases out of ten. If one first speaks of sorrow, grief, joy, and anger, of dryness, dampness, cold, and summer-heat, of yin and yang, and of women, I ask about the reasons why these are so — the lowly and the noble, the poor and the wealthy, and what the human body follows accordingly; how those below are made to serve, and how, when facing affairs, one may make them fit the Way and its art — I have respectfully received these instructions. I ask further to raise a foolish and lowly question, one not found in the classics, and wish to hear its explanation. The Emperor said: This is a great matter indeed. Lei Gong then asked: Why is it that when a person weeps and cries, sometimes no tears come out, or if tears come out there is little nasal mucus — what is the reason for this? The Emperor said: This is found in the classics. He asked further: I do not know where this water arises from, nor where the mucus comes from. The Emperor said: As for this question, it is of no benefit to treatment; yet it is something the physician should know, for it is born of the Way.
Now, the heart is that which concentrates the essence of the five viscera; the eyes are its orifice, and the radiant complexion is its outward flourishing. Thus, when a person is in a state of well-being, the qi is harmonious in the eyes; when there is loss, grief is made known in the complexion. Thus, when there is sorrow and grief, tears fall; the falling of tears is where this water arises. The ancestral source of this water is the accumulated water within the body; the accumulated water is the utmost yin; the utmost yin is the essence of the kidney. The reason this ancestral essential water does not normally flow out is that the essence holds it in check; it supports and encloses it, and thus the water does not flow. Now, the essence of water is the will, and the essence of fire is the spirit; when water and fire resonate with each other, spirit and will are both moved to sorrow, and thus the water of the eyes is produced. Hence the common saying goes: 'sorrow of the heart is called sorrow of the will,' for the will and the essence of the heart converge together at the eyes. Thus, when both are sorrowful, the spirit qi is transmitted to the heart, but the essence does not rise to be transmitted to the will, so that the will alone is sorrowful, and hence tears come forth.
Tears and mucus arise from the brain. The brain belongs to yin; the marrow is what fills the bones, and thus the brain seeps forth as mucus. The will governs the bones; thus, when the water flows, the mucus follows it, for they move together as members of the same category. Now, mucus and tears are like brothers to one another: in urgency they perish together, in life they live together. When the will is already sorrowful, mucus and tears both come forth and flow freely together. That mucus and tears both come forth and follow one another is because they belong to the same category.
Lei Gong said: This is profound indeed! I ask further: why is it that when a person weeps and cries, sometimes tears do not come out, or if they come out there is little mucus that does not follow along with them? The Emperor said: When tears do not come out, it is because the crying is not truly sorrowful. When one does not weep, it is because the spirit is not compassionate. If the spirit is not compassionate, then the will is not sorrowful; yin and yang hold each other in check, so how could tears come forth alone? Now, when the will is sorrowful, there is grieved distress; when there is grieved distress, it surges into yin; when it surges into yin, the will departs from the eyes; when the will departs, the spirit no longer guards the essence; when essence and spirit depart from the eyes, mucus and tears come forth. Moreover, have you alone not recited and pondered the words of the classics? In reversal, the eyes see nothing. Now, when a person experiences reversal, yang qi combines above and yin qi combines below. When yang combines above, it is like the dazzling light of fire; when yin combines below, the feet become cold, and when the feet are cold, there is distension. Now, a single water cannot overcome five fires, and so the corners of the eyes become obscured. Thus, when facing the wind, tears fall without ceasing. When wind strikes the eyes, yang qi guards the essence within, and this is fire qi scorching the eyes; hence, on encountering wind, tears fall. There is an analogy for this: when fire is fierce, wind is generated, and this can then produce rain — this belongs to the same category of phenomena.