辨质者。辨明其舌之木质也。其质虽满舌属胃。而内含经络甚多。与心脾肝肾实互
相关系。凡病之虚实。症之吉凶。多于此中诊断之。故辨质较观形察色。尤为扼要。
凡舌质坚敛而兼苍老。不论苔色白黄灰黑。病多属实。舌质浮胖而兼娇嫩。不拘苔
色灰黑黄白。病多属虚。此辨舌质老嫩。断病虚实之要诀。
凡舌质柔软。伸缩自由者。气液自滋。舌质强硬。伸缩为难者。脉络失养。但舌强
与舌短不同。舌短者舌系收紧。舌强者舌质坚硬。此辨舌质软硬。察液润燥之要诀。
凡看舌质。先辨干滑燥润。干者津乏。扪之而涩。滑者津足。扪之而湿。燥者液涸
。扪之而糙。润者液充。扪之而滑。如病初起而舌即干者。津竭可知。病久而舌尚润者
。液存可识。望之若干。扪之却滑者。若湿热蒸浊。其色黄亮。若瘀血内蓄。其色紫黯。
望之若润。扪之却燥者。若气浊痰凝。其苔白浓。若气虚伤津。其苔白薄。他如阴虚阳
盛者。其舌必干。阳虚阴盛者。其舌必滑。阴虚阳盛而火旺者。其舌必干而燥。阳虚阴
盛而火衰者。其舌必滑而润。此辨舌质干滑燥润。断病津液充乏。阴阳盛衰之要诀。
凡舌质有光有体。不论白黄灰黑。刮之而里面红润。神气荣华者。凡病多吉。舌质
无光无体。不拘有苔无苔。视之
而里面枯晦。神气全无者。凡病皆凶。此辨舌质荣枯。断病吉凶之要诀。
凡舌圆大碎嫩。其质红润者。皆属心经虚热。病尚可治。舌枯小卷短。其质焦紫者
。皆属肝肾阴涸。病多速死。此辨舌质圆嫩枯短。断病虚热阴涸之要诀。
凡舌色如朱柿。光如镜面或如去膜猪腰子。或敛束如荔枝壳。或干枯红长。而有直
纹透舌尖者。病皆不治。尚属显而易见之舌质已枯。更有生气虽绝。而舌质上面。反罩
一层苔色。洁白似雪花片。呆曰如豆腐渣。或如嚼碎饭子。 白兼青。枯白而起糜点。
视其舌边舌底。必皆干晦枯痿。一无神气。乃舌质已坏。脏气皆绝也。病皆速死。此辨舌
质无神无气。断病必死之要诀。
Differentiating the tongue body involves identifying its fundamental structure. Although the entire tongue is associated with the Stomach, it contains numerous meridians and is closely interconnected with the Heart, Spleen, Liver, and Kidney. The deficiency or excess nature of diseases, as well as the auspicious or ominous prognosis of symptoms, can mostly be diagnosed through the examination of the tongue body. Therefore, differentiating the tongue body is more crucial than observing the tongue coating's shape and color.
When the tongue body is firm, tight, and appears aged or coarse, regardless of whether the coating is white, yellow, gray, or black, the condition is mostly Excess (Shi). When the tongue body is swollen, puffy, delicate, and tender, regardless of whether the coating is gray, black, yellow, or white, the condition is mostly Deficiency (Xu). This is the key to determining the deficiency or excess of a disease by distinguishing between an "aged" (lao) and "tender" (nen) tongue body.
When the tongue body is soft and moves freely, it indicates that Qi and fluids are nourishing. When the tongue body is stiff and difficult to move, it indicates that the collaterals are lacking nourishment. However, "stiff tongue" (She Qiang) differs from "short tongue" (She Duan). A short tongue results from the tightening of the lingual frenulum, whereas a stiff tongue refers to the hardness of the tongue body itself. This is the key to examining the moisture or dryness of fluids by distinguishing between soft and hard tongue bodies.
When observing the tongue body, one must first distinguish between dry, slippery, rough, and moist states. Dryness indicates a lack of fluids, feeling rough to the touch. Slipperiness indicates sufficient fluids, feeling wet to the touch. Roughness indicates depleted fluids, feeling coarse to the touch. Moisture indicates abundant fluids, feeling smooth to the touch. If the tongue is dry at the onset of illness, it indicates exhaustion of fluids; if the tongue remains moist after a long duration of illness, it indicates the presence of fluids. If the tongue appears dry but feels slippery to the touch, it may be due to damp-heat steaming turbid pathogens, presenting with a bright yellow color; or due to internal accumulation of blood stasis, presenting with a purple-dark color. If the tongue appears moist but feels dry to the touch, it may be due to turbid Qi and congealed phlegm, presenting with a thick white coating; or due to Qi deficiency damaging fluids, presenting with a thin white coating. Furthermore, in cases of Yin deficiency with Yang hyperactivity, the tongue will be dry; in cases of Yang deficiency with Yin hyperabundance, the tongue will be slippery. In cases of Yin deficiency with Yang hyperactivity accompanied by blazing fire, the tongue will be dry and rough; in cases of Yang deficiency with Yin hyperabundance accompanied by declining fire, the tongue will be slippery and moist. This is the key to determining the sufficiency or insufficiency of fluids and the balance or imbalance of Yin and Yang by distinguishing between dry, slippery, rough, and moist tongue bodies.
If the tongue body has luster and form, regardless of whether the coating is white, yellow, gray, or black, and upon scraping, the interior is red and rosy with a flourishing spirit, the prognosis for most diseases is auspicious. If the tongue body lacks luster and form, regardless of the presence or absence of coating, and the interior appears withered and dull without any spirit, the prognosis for all diseases is ominous. This is the key to determining the auspicious or ominous prognosis of a disease by distinguishing between a vibrant/flourishing (rong) and withered/dull (ku) tongue body.
If the tongue is round, large, fragmented, and tender with a red and rosy body, it belongs to Deficient Heat in the Heart Meridian, and the disease is treatable. If the tongue is withered, small, curled, and short with a scorched purple body, it belongs to Exhaustion of Yin in the Liver and Kidney, and the disease often leads to rapid death. This is the key to distinguishing between Deficient Heat and Yin exhaustion by observing the round/tender versus withered/short characteristics of the tongue body.
If the tongue color is like a persimmon, shiny as a mirror, or like a pig kidney without membrane, or tightly gathered like a lychee shell, or dry, red, elongated with straight lines extending to the tip, these conditions are incurable. These are obvious signs of a withered tongue body. Even worse, although vital energy is exhausted, a layer of coating may appear on the tongue surface, white like snowflakes, stiff like tofu dregs, or like chewed rice grains, white mixed with green, dry and white with eroded spots. Examining the sides and underside of the tongue reveals they are dry, dull, withered, and flaccid, devoid of spirit. This indicates that the tongue body is ruined and the Qi of the Zang organs is completely exhausted, leading to rapid death. This is the key to determining a fatal prognosis by identifying a tongue body devoid of spirit and Qi.