尝思诊面之法。非特明堂五色。面貌五官。可分五脏也。其面形亦有可分者二。一则因形层以分之。如肝
合筋。心合脉。脾合肉。肺合皮。肾合骨。筋者肝之部。脉者心之部。肉者脾之部。皮者肺之部。骨者肾之部。推
而论之。皮有浓薄泽夭。肉有肥瘦消长。脉有小大迟数。筋有粗细缓急。骨有大小坚脆。太过者为有余。不
及者为不足。皆可辨其盛衰虚实焉。此形层之分也。一则因经络以分之。如督脉自背中行而上头至鼻。
任脉自腹中行而上颐循面。冲脉荣于唇口。跷脉会于睛明。听宫颧 之分。手太阳也。眉冲五处之分。足
太阳也。迎香禾 之分。手阳明也。颊车巨 之分。足阳明也。耳门和 之分。手少阳也。前关听会之分。足
少阳也。推而论之。肿起者为实。陷下者为虚。肿起为太过。其病在外。陷下为不及。其病在内。此经络之分
也。由是触类旁通。即一指之小。四体之大。其形层经络。无不皆然。至若因证言病。如诸书所谓大头瘟。两
目鼻面肿者。阳明。耳前后并额角肿者。少阳。脑后项下肿起者。太阳。面肿曰风。面目肿大。时热。脉沉滑。中
有水气。曰风水。面浮肿。气逆多涕唾。曰咳上气。面浮肿。息肩。脉浮大。曰不治。短气面肿。鼻不闻香。咳嗽唾
痰。两胁胀痛。喘息不定。曰肺劳。面目浮肿。曰阳虚胃冷。面目浮肿至项。曰阳虚气结。病患营卫竭绝。面浮
肿。曰死。面肿色苍黑。曰死。咳嗽羸瘦。脉坚大。曰死。咳嗽脱形发热。脉小坚急。曰死。肌瘦下脱。形热不去。曰
死。两腮消瘦缩入。曰胃虚肉绝。外此而痘疹、痈疽、疠风、时疫。其病在头面者。皆可按部位。分经络。合之面
容。参之面色。以辨其同异。而判其吉凶也。然其中肿起为实。浮肿为虚。何也。盖形之聚散不同。色之泽夭
亦异。实者邪气实。虚者正气虚。肿而属虚者。邪气实而正气虚也。推之于痘疹痈疽。其义一也。
我曾思考诊察面部的方法。不仅明堂（鼻部）的五色变化、面貌五官的形态，可以分别对应五脏；面部的形状也有两种可分类的方法。
第一种是根据形体层次来区分。例如：肝与筋相合，心与脉相合，脾与肉相合，肺与皮相合，肾与骨相合。筋是肝的外候部位，脉是心的外候部位，肉是脾的外候部位，皮是肺的外候部位，骨是肾的外候部位。由此推论开来，皮肤有厚薄、润泽或枯槁的区别；肌肉有肥瘦、消长（萎缩或丰满）的区别；血脉有大小、迟数（缓慢或快速）的区别；筋腱有粗细、缓急（松弛或紧张）的区别；骨骼有大小、坚固或脆弱区别。过于亢盛属于有余，不及则属于不足。这些都可以辨别脏腑气血的盛衰虚实情况。这就是根据形体层次的区分。
第二种是根据经络循行来区分。例如：督脉从背部正中上行至头部直至鼻部；任脉从腹部正中上行至下颌并沿着面部循行；冲脉荣华于嘴唇和口角周围；跷脉会合于睛明穴；听宫穴及颧骨区域的分属，属于手太阳小肠经；眉冲穴、五处穴区域的分属，属于足太阳膀胱经；迎香穴、禾髎穴区域的分属，属于手阳明大肠经；颊车穴、巨髎穴区域的分属，属于足阳明胃经；耳门穴、和髎穴区域的分属，属于手少阳三焦经；前关穴、听会穴区域的分属，属于足少阳胆经。由此推论开来，肿胀突起者属于实证，凹陷下陷者属于虚证。肿胀突起为邪气太过，其病位在体表；凹陷下陷为正气不及，其病位在体内。这就是根据经络的区分。
由这种触类旁通的方法，即使是手指这样的小部位，还是四肢这样的大部位，其形体层次和经络分布的道理没有不相同的。至于通过言语症状来判断疾病，如各种医书所说的：大头瘟病，出现两眼、鼻子、面部肿胀的，属于阳明经病变；耳朵前后及额角肿胀的，属于少阳经病变；脑后及项下部肿胀突起的，属于太阳经病变。面部浮肿称为风病；面目肿大，时常发热，脉象沉滑，体内有水气停留的，称为风水病；面部浮肿，气息上逆，多涕唾的，称为咳上气病；面部浮肿，呼吸时耸肩，脉象浮大无根的，属于不治之症；短气且面部浮肿，鼻子闻不到气味，咳嗽吐痰，两侧胁肋胀痛，喘息不定的，称为肺劳病；面目浮肿的，属于阳气虚弱、胃中寒冷；面目浮肿延伸至颈部，属于阳气虚弱、气机郁结。如果病人的营气和卫气枯竭断绝，出现面部浮肿，属于死证；面部浮肿且颜色青黑，属于死证；咳嗽且身体消瘦，脉象坚硬而大，属于死证；咳嗽且形体脱失、发热，脉象细小坚硬急促，属于死证；肌肉消瘦、下肢肌肉萎缩脱落，身体发热不退，属于死证；两腮消瘦缩入，属于胃气虚弱、肌肉败绝。除此之外，像痘疹、痈疽、疠风（麻风）、时疫等病症，凡是在头面部表现的，都可以按照部位，划分经络，结合面容形态，参考面色变化，来辨别疾病的异同，从而判断吉凶预后。然而其中为什么肿胀突起属于实，浮肿属于虚呢？这是因为形体的聚散不同，颜色的润泽或枯槁也各异。实证是邪气盛实，虚证是正气虚弱。而有些肿胀却属于虚证的，是因为邪气盛实而正气同时也虚弱。推广到痘疹、痈疽等疾病，其中的道理也是一样的。
I have pondered the methods of facial diagnosis. It is not only that the five colors of Mingtang (the nose) and the features of the face and five organs can be distinguished to correspond to the Zang organs; the shape of the face also has two ways of classification.
The first method distinguishes based on morphological layers. For instance: the Liver corresponds to tendons, the Heart corresponds to vessels, the Spleen corresponds to flesh, the Lung corresponds to skin, and the Kidney corresponds to bones. Tendons are the external domain of the Liver, vessels are the external domain of the Heart, flesh is the external domain of the Spleen, skin is the external domain of the Lung, and bones are the external domain of the Kidney. Extending this reasoning, skin varies in thickness and luster or witheredness; flesh varies in fatness or leanness, atrophy or fullness; vessels vary in size and pulse rate (slow or rapid); tendons vary in thickness and tension (slack or tight); bones vary in size and robustness or fragility. Excess indicates surplus, while deficiency indicates insufficiency. These can all be used to distinguish the prosperity, decline, excess, and deficiency of the internal organs and Qi-blood. This is the distinction based on morphological layers.
The second method distinguishes based on meridian pathways. For instance: the Du Mai (Governing Vessel) ascends from the midline of the back to the head and reaches the nose; the Ren Mai (Conception Vessel) ascends from the midline of the abdomen to the chin and follows the face; the Chong Mai (Penetrating Vessel) flourishes around the lips and mouth; the Qiao Mai (Yang-Heel and Yin-Heel Vessels) converge at Jingming (BL1); the area of Tinggong (SI19) and the cheekbones belongs to the Hand-Taiyang Small Intestine Meridian; the areas of Meichong (EX-HN2) and Wuchu (BL3) belong to the Foot-Taiyang Bladder Meridian; the areas of Yingxiang (LI20) and Heliao (SI18) belong to the Hand-Yangming Large Intestine Meridian; the areas of Jiache (ST6) and Juliao (ST3) belong to the Foot-Yangming Stomach Meridian; the areas of Ermen (TE21) and Hezhao (SJ22) belong to the Hand-Shaoyang Sanjiao Meridian; the areas of Qianguan (EX-HN4) and Tinghui (GB2) belong to the Foot-Shaoyang Gallbladder Meridian. Extending this reasoning, swelling and protrusion indicate excess patterns, while depression and sinking indicate deficiency patterns. Swelling and protrusion signify excessive pathogenic factors, indicating the disease is in the exterior; depression and sinking signify insufficient healthy Qi, indicating the disease is in the interior. This is the distinction based on meridians.
By analogical reasoning from this, whether it is a small part like a finger or a large part like the four limbs, the principles of morphological layers and meridians are universally applicable. Regarding diagnosing diseases through verbal symptoms, as described in various medical texts: for Big Head Plague (Datou Wen), where both eyes, nose, and face swell, the pathology lies in the Yangming channel; swelling around the ears and forehead angles lies in the Shaoyang channel; swelling at the back of the head and neck lies in the Taiyang channel. Facial edema is termed Wind Disease; facial and ocular swelling with intermittent fever and a deep, slippery pulse, indicating water retention in the body, is termed Fengshui (Wind-Water) Disease; facial edema with rebellious Qi, excessive phlegm and saliva, is termed Cough with Rebellious Qi; facial edema with shoulder shrugging during respiration and a floating, large pulse, is considered an untreatable condition; shortness of breath with facial edema, anosmia, coughing with sputum, distending pain in both hypochondria, and irregular panting is termed Feilao (Lung Consumption); facial and ocular edema indicates Yang deficiency and Cold in the Stomach; facial and ocular edema extending to the neck indicates Yang deficiency and Qi stagnation. If a patient's Ying (Nutritive) and Wei (Defensive) Qi are exhausted and severed, presenting with facial edema, it is a death sign; facial edema with cyanotic-black complexion is a death sign; coughing with emaciation and a hard, large pulse is a death sign; coughing with physical depletion and fever, and a small, hard, rapid pulse is a death sign; muscle wasting with lower limb muscle atrophy and persistent heat is a death sign; sunken and shrunken cheeks indicate Stomach Qi deficiency and exhaustion of flesh. Besides these, for conditions such as variola (smallpox/variolae), carbuncles and sores, leprosy (Lifeng), and seasonal epidemics manifesting on the head and face, one can analyze by location, differentiate by meridians, combine with facial morphology, and reference facial color to distinguish similarities and differences, thereby judging auspiciousness or ominous outcomes. However, why is swelling considered excess and edema considered deficiency? This is because the aggregation and dispersion of form differ, just as the luster or witheredness of color varies. In excess patterns, pathogenic factors are strong; in deficiency patterns, healthy Qi is weak. When swelling is attributed to deficiency, it means pathogenic factors are strong while healthy Qi is simultaneously weak. The principle remains the same when extended to conditions like variola and carbuncles.