Dysentery with tenesmus (a feeling of incomplete defecation and straining): If it presents as a Shaoyin syndrome with drowsiness (欲寐) and cold extremities (Si Ni), use Si Ni Tang (Four Counterflow Decoction) added with Xie Bai (Allium macrostemon Bulb). If it is a heat syndrome, use Bai Tou Weng Tang (Pulsatilla Decoction) (for formula discussion, see under "Diarrhea").

If the pulse is floating, sweating should be used to resolve the exterior. If moxibustion is applied, the pathogenic factor cannot exit; instead, it becomes exacerbated by fire. The disease will cause heaviness and numbness below the waist, termed "Fire Reversal" (Huo Ni).

If the pulse is slow, floating, and weak, with aversion to wind and cold, this is an exterior syndrome. If the physician erroneously uses purgation, the patient may lose appetite, experience hypochondriac pain, jaundice (yellowing of the body), stiff neck, and difficult urination. Administering Chai Hu Tang (Bupleurum Decoction) at this stage will inevitably cause tenesmus (for discussion, see under "Hypochondriac Pain").

In diarrhea, if the pulse is deep and wiry, there is tenesmus.

When a patient has high fever but desires to wrap themselves in clothing, it indicates heat on the skin (superficial level) and cold in the bone marrow (deep level). When a patient has severe cold sensation but does not desire to wrap themselves in clothing, it indicates cold on the skin and heat in the bone marrow. (Cheng Wuji's commentary: "Skin" refers to the superficial/exterior, while "bone marrow" refers to the deep/interior. Fever with desire for clothing indicates exterior heat and interior cold; cold sensation without desire for clothing indicates exterior cold and interior heat.)

Danbo Yuanjian notes: High fever with a desire for clothing likely occurs because the body cannot generate warmth internally; however, if the exterior qi is sufficient, it can self-warm and resist wind-cold. In a high-fever condition, the exterior qi should be robust and prefer coolness. The fact that the patient desires clothing suggests deficient exterior qi insufficient for self-warming. This may indicate that the patient's yin is weak, causing yang to float away unattached, manifesting as high fever. This should be treated as yin deficiency. Severe cold sensation without desire for clothing may indicate pathogenic factors in the exterior failing to generate heat spontaneously. Although there is no external heat, pathogenic stagnation in the skin and pores makes the exterior qi overly full, hence the aversion to clothing. This should be treated as a stagnation syndrome. The commentary stating "exterior heat, interior cold" implies that the heat pathogen was shallow, while the cold pathogen was deep within. "Exterior cold, interior heat" implies the cold pathogen was shallow externally, while the heat pathogen was deep internally. Are these conditions caused by "double contraction" (re-infection)? Diseases of double contraction have specific names, e.g., Taiyang disease contracting cold again becomes Warm Malaria; contracting wind becomes Wind-Warmth; contracting warm-heat becomes Warm Toxin; contracting warm qi becomes Warm Epidemic Disease; dampness contracting again becomes Damp-Warmth. There is traditionally no concept of "exterior heat/interior cold" or vice versa. However, what disease do these represent? I have sought the meaning in the text, suspecting it arises from the depth of cold/heat pathogens. The *Nei Jing* states: "Excess leads to harm, succession brings regulation." When qi reaches extreme excess, it is controlled by its opposing element. Deep heat causes external aversion to cold, so "cold on the skin" is actually heat; "heat in the bone marrow" is a case of extreme fire resembling water. Zhang Zhongjing said: "Cold injury leads to heat disease." Even severe heat is not fatal. Deep cold causes external fever, so "heat on the skin" is actually cold; this is cold injury manifesting as intense heat. The *Nei Jing* states: "Treat extremes with reverse methods," and "Use cold for heat, use heat for cold." When disease qi is deep, righteous qi is also deficient. Without reverse treatment, how can pathogenic factors be subdued and the disease resolved?

Zhao Xianke elaborates: Zhang Zhongjing distinguishes only between skin and bone marrow, not exterior and interior, because skin, flesh, vessels, sinews, and bones are associated with the five zang organs externally, filling the body. Only zang and fu organs allow for the discussion of exterior and interior. Thus, skin is the superficial exterior above the bone marrow, and bone marrow is the deep interior below the skin, differing from the example where meridians are exterior and zang-fu are interior. Moreover, placing this syndrome at the beginning of the Taiyang chapter confirms it is an exterior syndrome. Therefore, in individuals with constitutional weakness and cold who contract pathogens and develop fever, the heat is superficial and cannot overcome deep cold, leading to external fear of cold and desire for clothing ("heat on skin, cold in bone marrow"); treatment requires acrid-warm herbs. Conversely, in robust individuals with constitutional heat, or those who consume alcohol, upon initial pathogen contraction, cold has not yet transformed into heat. Yin pathogen closes off latent heat externally, condensing outside while heat stagnates inside, causing internal vexation and aversion to clothing ("cold on skin, heat in bone marrow"); treatment requires acrid-cool herbs. Only after releasing the exterior and harmonizing righteous qi is the subtle brilliance of Zhang Zhongjing revealed. If one equates skin with exterior and bone marrow with interior, then the bone joint pain in Ma Huang Tang syndrome would incorrectly be classified as having both exterior and interior syndromes.

*Ren Shu* (Book of Human Life): Regarding "heat on skin, cold in bone marrow," Zhang Zhongjing provides no treatment method. It is appropriate to first administer Yang Dan Tang. Once cold is resolved, follow with Xiao Chai Hu Tang plus Gui Zhi to warm the interior. It also states: For exterior heat and interior cold, the pulse must be deep and slow, hands may be slightly cold, with diarrhea of undigested food. Thus, yin syndromes can present with fever, treated with Si Ni Tang or Tong Mai Si Ni Tang. Regarding "cold on skin, heat in bone marrow," Zhang Zhongjing also provides no treatment. It is appropriate to first use Bai Hu Jia Ren Shen Tang to remove heat, followed by Gui Zhi Ma Huang Ge Ban Tang to resolve the exterior. It also states: For exterior cold and interior heat, the pulse must be slippery and wiry with cold limbs, dry mouth, and dry tongue. Thus, Shaoyin syndrome with aversion to cold, curling up, constant inner vexation, and desire for light clothing is cured by purging with Da Chai Hu Tang. These are the遗意 (legacy intentions) of Zhang Zhongjing.