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To treat blood-wind sores (blood-heat dermatitis) on both feet, and wind-damp sores with pain and itching penetrating to the bone on both shoulders and back.
Mache Chi Xian (Portulaca Oleracea Herb, chopped, dried in a warm oven, 5 qian), Huang Dan (Lead Tetroxide, refined), Huang Bo (Phellodendri Cortex), Ku Bai Fan (Alumen Calcined), Hai Er Cha (Catechu, each 3 qian), Qing Fen (Calomel, 1 qian).
Grind into fine powder, mix evenly, then add Calomel. Mix with raw Tung Oil, spread onto thick Tung Oil paper. Wash the affected area with Scallion and Pepper Decoction, then apply the plaster.

In severe winter, when the climate is biting and all things gather and store, those who contract cold are relatively few, because people know how to avoid it. However, cold and heat at dawn and dusk, wind and rain out of season, exposure to cold air, and consumption of cold drinks or food—all these are self-inflicted cold pathogens. The Lung is the head of the Zang organs; upon contracting cold, it causes wheezing and coughing, rebellious Qi, fever, and dry, brittle hair. The Stomach is the head of the Fu organs; upon contracting cold, it causes vomiting, nausea, thirst, irritability, and fever. Those with thin constitutions may develop symptoms immediately upon exposure, while those with robust constitutions may have symptoms manifest only after accumulation over time. As stated in the *Classic*: "If one is injured by cold in winter, one will surely suffer from warm diseases in spring." This refers to conditions that manifest after accumulation. For example, in cases of Cold Strike (Zhong Han), where there is coldness of the hands and feet, shivering, locked jaw, salivation, and inability to cry, this represents immediate onset upon exposure. Furthermore, there is congenital cold contracted in the womb, resulting in a bluish-white complexion, cold limbs, intestinal colic with drawing pain, locked mouth unable to open, abdominal pain due to visceral cold, known as Fetal Cold (Tai Han); this represents the deepest accumulation of cold. However, Cold patterns closely resemble Heat patterns because Yang Qi is forced outward and upward. One must observe not only the obvious manifestations but also the subtle internal mechanisms, requiring careful examination. For instance, rapid pulse, desire for water, irritability, thirst, and restlessness indicate Heat disease. Conversely, new-onset cough with clear sputum, non-astringent urination, cold limbs, undigested food in stool, cool body without thirst, and slow pulse all belong to Cold patterns. Although cold limbs mostly indicate Cold, occasionally Yin and Yang are imbalanced, preventing the smooth circulation of Qi. Thus, Yang Qi accumulates internally and cannot circulate to the four limbs, a condition known as "the deeper the heat, the deeper the cold extremities" (Re Shen Jue Ye Shen). This requires careful differentiation. Therefore, it is said: Cold and Heat are like water and fire; misdiagnosis can be fatal. Zhu Danxi stated: For Cold patterns, hot medicines must be administered. However, hot medicines should be combined with cooling agents as guides, or taken frozen, so that the medicine's nature resonates with the disease, which aligns with the *Classic*'s principle of "following the pathogenic factor while treating contrary to its nature."