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When there is severe edema of the face, eyes, and limbs, it is because the pathogen is internal while the symptoms manifest externally. Using the pulp and seeds of *Cucumis melo var. flexuosus* (Ku Hu) to treat it means discarding the exterior and utilizing the interior essence.
The pulp and seeds are where the fluid essence of the melon is stored. As they gradually dry and contract, their qi becomes vigorous and their medicinal power concentrated, refining the fluid essence into pure extract. Using this to control the stagnant water in the human body will naturally cause the water to submit and obey constraints. So how does the melon function? Its flavor is bitter and cold, and its nature is descending. Since the melon has a descending nature, what could be more fitting for descending? This is why the *Shennong Bencao Jing* lists it at the end under drugs for draining downward water.

(Sang Er, wood ear fungus growing on mulberry trees. Although there are five colors, we discuss only the black variety here.)
Mulberry trees are the refined essence of the Ji Star. When they rot, through the steaming and vaporization of summer heat and dampness, they condense into ears (fungi). This is akin to kidney yin fluids ascending to the lungs, hence the black color. Possessing the innate nature of favoring wind, it enters the Liver channel. Therefore, it is most effective for damp-heat in the Blood level. Damp-heat in the Blood level is prone to disease in women. Leukorrhea with red and white discharge occurs when Yin is forced downward by Yang heat. Blood stasis forming masses and accumulations occurs when Yin is obstructed by Yang heat leading to stagnation. Yin-type cold-heat disorders occur when Yin is burdened by Yang heat and seeks to struggle. This indicates Yin deficiency, not Yang excess. One should transform Yin to raise Yin, rather than suppress Yang to damage Yang. Sang Er has a cool, moistening nature with ascending and vaporizing properties, thus it can transform Yin to raise Yin.

Xing Ren (Apricot Seed) possesses meridians, making it a fruit associated with the Heart; its kernel primarily unblocks Qi in the meridians, making it a fruit associated with the Lung. Its nature is directly descending and also laterally expanding. Lateral expansion and direct descent constrain each other, preventing either from fully exerting itself; therefore, without adding other herbs, it cannot laterally expand nor directly descend. However, when using Xing Ren for lateral expansion, one often simultaneously utilizes its direct descent. When using Xing Ren for direct descent, one often simultaneously utilizes its lateral expansion. If a condition requires both, Xing Ren can demonstrate both skills.
Ma Huang Tang is a sweating formula for treating Shang Han (Cold Damage). Since Ma Huang is already used, why add Xing Ren? Because Xing Ren can also direct Qi downward and stop wheezing. Exterior excess with unresolved pathogens causes wheezing; even after pathogens resolve, if Qi fails to descend, wheezing persists. Xing Ren travels to the exterior and enters the interior; thus, the Qi dispersed outward will also descend via the central pathway. Hence, Ma Xing Gan Shi Tang contains both Ma Huang and Xing Ren to treat wheezing. Ge Gen Tang contains Ma Huang but no Xing Ren because the condition originally lacked wheezing. However, Ma Huang does treat wheezing. Xiao Qing Long Tang states "remove Ma Huang and add Xing Ren for wheezing." Why the difference? Ma Huang ascends to emit Heart fluids and descends to unblock Kidney Qi. In Xiao Qing Long Tang syndrome, water below the heart attracts water from the Kidneys. If Ma Huang is used again to stir Kidney Qi, wheezing will become uncontrollable. Xing Ren treats the Lung, not the Kidney, so removing Ma Huang and adding Xing Ren is appropriate. This illustrates using Xing Ren for lateral expansion while taking advantage of its direct descent.
Da Xian Xiong Wan is a purgative formula for Shang Han. Chest binding with neck stiffness resembling Rou Ji (soft spasm) indicates that while the external neck stiffness resembles Da Xian Xiong Tang syndrome, the condition is more severe. Thus, Da Xian Xiong Tang can attack rapidly to cure, whereas this formula must change to pills for slow attack. Xing Ren alone is specifically set for neck stiffness. Neck stiffness is caused by Yang pathogens scorching fluids. Xing Ren, ground like paste, has a nature of lateral expansion. Assisted by Mang Xiao's moisture and Bai Mi's sweetness, transforming stiffness into flexibility is easy. However, chest binding neck stiffness requires purging and sinking. Xing Ren is indeed a merit-worthy assistant to Da Huang and a beneficial friend to Ting Li and Gan Sui. This illustrates using Xing Ren for direct descent while taking advantage of its lateral expansion.
For sweating in Shang Han, Ma Huang is primary and Xing Ren secondary; for treating wheezing, Xing Ren is primary and Ma Huang secondary. Thus, using them together yields rapid effects. Wheezing in Shang Han is due to exterior excess and Lung constraint. In miscellaneous diseases, there are heat wheezing, deficiency wheezing, and fluid-wheezing, among others. Removing Ma Huang and adding Xing Ren in Xiao Qing Long Tang implies it is not treating Shang Han wheezing, so the formula is often used for miscellaneous diseases. However, Zhang Zhongjing's method of medication relies on subtle shifts in combination and dosage to achieve vastly different results. Da Qing Long Tang is a crucial formula for Shang Han. Are Ma Huang and Xing Ren used together for wheezing? No. The reason is that Ma Huang dose is doubled compared to Ma Huang Tang, while Xing Ren is reduced from 70 to 40 grains. With Sheng Jiang's ascending dispersion and Shi Gao's cold nature, Xing Ren follows Ma Huang in lateral expansion rather than focusing on direct descent. By inference, there are four other formulas where Ma Huang and Xing Ren are used together not for wheezing:
1. Ma Huang Jia Zhu Tang: For damp patients with body ache, cold-damp is constrained in the muscle layer. Ma Huang Tang is suitable. Adding Bai Zhu absorbs dampness. With strengthened Middle Qi, Xing Ren merely benefits Lung Qi.
2. Ma Huang Xing Ren Yi Yi Gan Cao Tang: For wind-damp injury causing fever worsening at dusk. Ma Huang and Xing Ren alone cannot treat this. Yi Yi Ren clears heat and removes dampness, treating chronic wind-damp bi. Dosages are small: Ma Huang is 1/6 of Ma Huang Tang dose, Xing Ren is 1/7, Yi Yi Ren matches Ma Huang. This is a small dose treating upper jiao, so Xing Ren lacks the power of direct descent.
3. Wen Ge Tang: This is Da Qing Long Tang minus Gui Zhi. Thirst is due to intense heat, so Wen Ge and Shi Gao are abundant. Ma Huang is halved because exterior pathogens are mild and excessive sweating is unwanted. Without the salty-cold Wen Ge and Shi Gao, Ma Huang might reach 3 liang. But with Sheng Jiang and Xing Ren assisting Ma Huang, sweating is inevitable. Although Xing Ren has direct descent, it is controlled by Wen Ge/Shi Gao, distancing it from Ma Huang/Sheng Jiang dynamics.
4. Nong Po Ma Huang Tang: A modification of Xiao Qing Long Tang with different treatment. Cough with floating pulse: Gan Jiang, Wu Wei Zi, Xi Xin treat cold cough, indicating cold etiology. Ma Huang, Xing Ren, and Nong Po are warm dispersants, indicating exterior cold requiring release. Xi Xin plus Ban Xia dispels fluid. Wu Wei Zi plus Xiao Mai calms the Lung. This suggests early Fei Wei (Lung萎), so Shi Gao preserves fluids and transforms dryness, similar to Xiao Qing Long Tang plus Shi Gao. However, Xiao Qing Long Tang treats established Fei Zhang (Lung distension) by driving cold-fluid downward, while this treats early Fei Wei by resolving exterior pathogens during floating pulse. Gui Zhi and Bai Shao are used in the former but not this. Nong Po at 5 liang without Bai Shao prevents Xing Ren from performing direct descent. Here, Xing Ren's lateral expansion is taken while its direct descent is discarded.

Xing Ren's direct descent and lateral expansion are neither fierce, relying on other herbs. Weighing the two, direct descent is slightly superior. Hence, Zhen Quan advocated sweating, while the *Bencao Jing* advocates directing Qi downward. Fu Ling Xing Ren Gan Cao Zhu: Commentators view Xing Ren as resolving nodules, but I believe it directs Qi downward. Why? Chest Bi with Qi obstruction and shortness of breath seems severe but is milder than the Zhi Shi Ye Bai Gui Zhi Tang syndrome. This is Phlegm-Fluid pathology with sufficient Yang, needing no Ye Bai or Gui Zhi. Thin fluid uses this formula; thick phlegm uses Ju Pi Zhi Sheng Jiang Tang. Thin fluid causing obstruction stems from difficult urination and fluid retention in the chest. *Bencao Jing* says Fu Ling treats reverse Qi in chest/hypochondrium, epigastric knotting pain, and promotes urination. Thus, Fu Ling resolves retained fluid nodules. Fu Ling's light permeability resolves tangible fluid. Xing Ren's bitter-warm descent addresses intangible Qi. Together, they open Bi and unblock obstruction. Other formulas for Chest Bi lack Gan Cao, but this one includes it because both Fu Ling and Xing Ren descend; without Gan Cao to hold them, they would pass through too quickly. Waitu Zou Ma Tang is a purgative. Sudden heart pain, abdominal fullness, constipation. Xu Zhongke calls it Ke Wu; Shen Munan calls it Jiao Chang Wu Sha. Ba Dou expels tangible solid pathogens; Xing Ren directs intangible deficient Qi downward as an emergency measure. This is similar to using Xing Ren in Fu Ling Xing Ren Gan Cao Tang, taking advantage of direct descent over lateral expansion.

There are cases where Xing Ren assists Ma Huang in sweating within cold formulas. There are three formulas for Jaundice in Shang Han Lun: Yin Chen Hao Tang drains damp-heat via urine for Yangming excess with difficult urination and slight abdominal fullness. Zhi Zi Bai Pi Tang treats yellow skin and fever; Bai Pi treats Yangming channels/organs, clearing surface damp-heat (Bielu notes it treats skin heat/redness; Zou says it acts between interior/exterior), assisted by Zhi Zi and Gan Cao as a mild downward diuretic. These do not involve Xing Ren. Ma Huang Lian Qiao Chi Xiao Dou Tang states "stagnant heat in the interior causes jaundice" without difficult urination or fever, implying Taiyang interior (per Ke Qin). Taiyang stagnant heat requires sweating. Surface-releasing herbs are rarely cold, but Yangming damp-heat dislikes hot herbs. Lian Qiao, Zi Pi, and Chi Xiao Dou handle interior heat/dampness, allowing Ma Huang and Xing Ren to disperse to the surface, resolving damp-heat via sweat. This treats Taiyang stagnant heat jaundice, not headache/body ache, so Ma Huang/Xing Ren doses are reduced from Ma Huang Tang and used in a cold formula without hindering its cooling action.

There are cases where Xing Ren treats edema precisely by NOT sweating. "Water gone, vomiting stopped, patient has facial edema" (Tan Yin Pian). You Shi says Stomach Qi is harmonized but Lung congestion remains; Ma Huang can unblock it. However, his explanation for using Xing Ren instead of Ma Huang is flawed. Ma Huang releases Yang like sweating; blood deficiency precludes sweating ("loss of blood means no sweat"). Edema requires unblocking blood collaterals, which both Ma Huang and Xing Ren can do.

There are cases where Xing Ren treats wheezing without sweating formulas. Gui Zhi Jia Nong Po Xing Ren Tang: Taiyang disease treated incorrectly with purgatives, no chest binding or diarrhea, only slight wheezing. Since wheezing is slight, exterior excess is minimal. Gui Zhi Tang does not resolve exterior excess; using Ma Huang for mild exterior excess is inappropriate. Nong Po disperses warmth better than Gui Zhi; combined with Gui Zhi Tang to resolve exterior, it avoids excessive sweating. However, if exterior resolves but Qi does not descend, wheezing persists. Xing Ren excels at directing Qi downward and aids exterior resolution. Replacing Ma Huang with Xing Ren is likely for this reason.

Xing Ren ground like paste is moistening, possessing both lateral expansion and direct descent, benefiting both Shang Han and miscellaneous diseases. Ma Ren Wan uses Xing Ren for direct descent amidst moistening. Ma Ren and Xing Ren both moisten dryness; Ma Ren expands Spleen constraints, Xing Ren suppresses Lung to direct downward (see Da Ma Ren), contributing to bowel movement. Da Huang Zhe Chong Wan uses Xing Ren for lateral expansion amidst moistening. This formula tonifies deficiency and moderates the Middle. Only Xing Ren guides Di Huang into collaterals for nourishing transformation; even Tao Ren is too harsh compared to insect drugs. Some use Xing Ren merely for moistening assistance, seeing neither expansion nor descent: Fan Shi Wan. Hard dry blood in the uterus cannot be removed by Tao Ren, Gan Qi, or insects as suppositories, let alone relying solely on Xing Ren for expansion/descent. Menstrual irregularity with intermittent flow and leukorrhea indicates hard dry blood in the uterus that cannot be urgently treated. Dry blood causes irregular menstruation; damp-heat ferments into leukorrhea. Treat leukorrhea first. Fan Shi dries dampness and clears heat. Without Xing Ren and Bai Mi to moderate and harmonize, efficacy would not be so rapid. She Chuang Zi San is also a suppository. It treats Yin cold with She Chuang Zi and Bai Fen (softening hardness); this treats leukorrhea with Fan Shi and Xing Ren (moistening dryness). Xing Ren is moist but not cloying, not reducing Fan Shi's power. Claiming it helps resolve nodules contradicts Zhang Zhongjing's intent.

Xing Ren's lateral expansion is less fierce than Ma Huang, suitable for Wind-Deficiency conditions, especially Wind on the head and face. Jie Gu said it treats Upper Jiao Wind-Heat. Dong Yuan said it eliminates Wind-Heat in the Lung. Shi Wan said "when Qi descends, Heat resolves and Wind scatters." I believe Wind scattering resolves Heat; it is not treating Wind-Heat with hot herbs. Kaibian's Xing Su treats Wind-Deficiency headache; Xing Ren paste applied to head/face treats Wind swelling; various formulas for head pain, body heat, Wind on head, and scalp itching/scaling all contain Xing Ren. Shu Yu Tang and Shu Yu Wan also contain Xing Ren. Their indicated conditions include dizziness and vertigo. Inferring from this, even though Jin Gui Shu Yu Wan has many Wind-dispersing herbs, it undoubtedly uses Xing Ren for Head/Face Wind. Regarding "Wind Qi causing hundred illnesses," thorough consideration of Xing Ren is essential.