经水者，阴血也。阴必从阳，故其色红，禀火色也。血为气之配，气热则热，气寒则寒，气升则升，气降则降，气
凝则凝，气滞则滞，气清则清，气浊则浊。往往见有成块者，气之凝也。将行而痛者，气之滞也。来后作痛者，气血俱
虚也。色淡者，亦虚也。错经妄行者，气之乱也。紫者，气之热也。黑者，热之甚也。人但见其紫者、黑者、作痛者、
成块者，率指为风冷，而行温热之剂，祸不旋踵矣。良由《病源》论月水诸病，皆曰风冷乘之。宜其相习而成俗也。或
曰∶黑，北方水之色也。紫淡于黑，非冷而何？予曰∶经曰亢则害，承乃制。热甚者，必兼水化。所以热则紫，甚则黑
也。况妇人性执而见鄙，嗜欲加倍，脏腑厥阳之火，无日不起，非热而何？若夫风冷，必须外得，设或有之，盖千百而
一、二者也。
本草药之命名，固有不可晓者，中间亦多有意义，学人不可以不察。以色而名者，大黄、红花、白前、青黛、乌梅
之类是也。以形而名者，人参、狗脊、乌头、贝母、金铃子之类是也。以气而名者，木香、沉香、檀香、麝香、茴香之
类是也。以质而名者，浓朴、干姜、茯苓、生熟地黄之类是也。以味而名者，甘草、苦参、淡竹叶、草龙胆、苦酒之类
是也。以能而名者，百合、当归、升麻、防风、滑石之类是也。以时而名者，半夏、茵陈、冬葵、寅鸡、夏枯草之类是
也。以石膏火 ，细研醋调封丹炉，其固密甚于脂，苟非有膏焉能为用。此兼质与能而得名，正与石脂同意。阎孝忠妄
以方解石为石膏，况石膏其味甘而辛，本阳明经药。阳明主肌肉，其甘也能缓脾益气，止渴去火，其辛也能解肌出汗，
上行至头，又入手太阴、手少阳。彼方解石者，止有体重、质坚、性寒而已。求其所谓有膏而可为三经之主治者焉在哉？
医欲责效，不亦难乎！
Menstrual blood (Jingshui) is Yin blood. Yin must follow Yang; therefore, its color is red, as it inherits the color of Fire. Blood is the counterpart of Qi. When Qi is hot, blood becomes hot; when Qi is cold, blood becomes cold; when Qi ascends, blood ascends; when Qi descends, blood descends; when Qi coagulates, blood coagulates; when Qi stagnates, blood stagnates; when Qi is clear, blood is clear; when Qi is turbid, blood is turbid. Often, clots are seen in menstrual blood, which is due to the coagulation of Qi. Pain occurring before the onset of menstruation is due to Qi stagnation. Pain occurring after menstruation is due to deficiency of both Qi and Blood. A pale color also indicates deficiency. Irregular or erratic flow is due to the disorder of Qi. A purple color indicates heat in Qi. A black color indicates extreme heat. People often see purple or black color, pain, and clots in menstrual blood, and uniformly attribute them to Wind-Cold, administering warm and hot remedies, thereby bringing disaster upon themselves almost immediately. This is largely because *Zhubing Yuanhou Lun* (Treatise on the Pathogenesis and Symptoms of All Diseases) attributes all menstrual disorders to invasion by Wind-Cold. No wonder this has become a common practice. One might ask: Black is the color of Water in the North. Purple is lighter than black; could it not be cold? I say: The medical classics state, "When things reach an extreme, they cause harm; only through control can balance be maintained." When Heat is extreme, it necessarily incorporates the transformation of Water. Therefore, heat results in a purple color, and extreme heat results in a black color. Moreover, women tend to be stubborn and have limited insight, with doubled desires. The Fire of Jueyang within the Zang-Fu organs rises every day; how can this not be considered Heat? As for Wind-Cold, it must be acquired externally. Even if such cases exist, they are rare, perhaps one or two in a thousand.
The naming of materia medica has aspects that are indeed hard to understand, but there is much meaning involved, which students must carefully examine. Those named by color include Da Huang (Rhei Radix et Rhizoma), Hong Hua (Carthami Flos), Bai Qian (Cynanchi Stauntonii Radix), Qing Dai (Indigo Naturalis), Wu Mei (Mume Fructus), etc. Those named by shape include Ren Shen (Ginseng Radix), Gou Ji (Cibotii Rhizoma), Wu Tou (Aconiti Radix), Bei Mu (Fritillariae Bulbus), Jin Ling Zi (Meliae Fructus), etc. Those named by aroma include Mu Xiang (Aucklandiae Radix), Chen Xiang (Aquilariae Lignum Resinatum), Tan Xiang (Santalum Album Lignum), She Xiang (Moschus), Hui Xiang (Foeniculi Fructus), etc. Those named by texture include Hou Po (Magnoliae Officinalis Cortex), Gan Jiang (Zingiberis Rhizoma), Fu Ling (Poria), Sheng Di Huang (Rehmanniae Radix) and Shu Di Huang (Rehmanniae Radix Preparata), etc. Those named by taste include Gan Cao (Glycyrrhizae Radix et Rhizoma), Ku Shen (Sophorae Flavescentis Radix), Dan Zhu Ye (Lophatheri Herba), Cao Long Dan (Gentianae Scabrae Radix et Rhizoma), Ku Jiu (Vinegar), etc. Those named by function include Bai He (Lilii Bulbus), Dang Gui (Angelicae Sinensis Radix), Sheng Ma (Cimicifugae Rhizoma), Fang Feng (Saposhnikoviae Radix), Hua Shi (Talcum), etc. Those named by season include Ban Xia (Pinelliae Tuber), Yin Chen (Artemisiae Scopariae Herba), Dong Kui (Malvae Semen), Yin Ji (a type of chicken/herb context dependent), Xia Ku Cao (Prunellae Spica), etc. Regarding Shi Gao (Gypsum Fibrosum), it contains a substance resembling paste/grease. When finely ground and mixed with vinegar, it can seal alchemical furnaces more tightly than grease. If it did not possess this "paste-like" quality, how could it be effective? This name derives from both its texture and function, similar to Shi Zhi (Aluminis Crystallatum). Yan Xiaozhong erroneously identified Fang Jie Shi (Pyromorphite) as Shi Gao. Furthermore, Shi Gao has a sweet and pungent taste and belongs to the Yangming Channel. The Yangming channel governs the muscles. Its sweetness can moderate Spleen Qi, benefit Qi, relieve thirst, and clear fire. Its pungency can release the muscle layer and induce sweating. Its action travels upward to the head and enters the Hand-Taiyin Lung Channel and Hand-Shaoyang Sanjiao Channel. In contrast, Fang Jie Shi possesses only weight, hardness, and cold nature. Where, then, is the evidence for it having a "paste-like" quality and serving as the primary treatment for these three channels? Is it not difficult for physicians to achieve efficacy under such misconceptions?