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Mu Mu (Anemarrhenae Rhizoma): Bitter in taste, cold in nature, with thick and slippery juice. Its color lies between yellow and white, thus it can enter the Stomach to clear exogenous heat. When combined with Shigao (Gypsum Fibrosum), it forms the Baihu Tang (White Tiger Decoction) (adding Gancao (Licorice Root) and Jingmi (Rice Grain) to these two herbs creates this formula, used for Yangming stage syndromes in Shanghan or Wenbing where heat has entered). It enters the Lung to moisten the dryness of Lung Metal. Since the Lung is the upper source of the Kidney, when combined with Huangbai (Phellodendri Cortex), it also nourishes Kidney Yin (adding a small amount of Rougui (Cinnamon Bark) as a guiding herb creates Zishen Wan, used for insufficient urination due to Yin deficiency failing to transform Yang). Because it is cold and rich in fluids, it strengthens Water to control Fire, treating bone-steaming tidal fever and eye conditions involving pterygium covering the sclera. Due to its cold, slippery fluid possessing a circulating nature, it eliminates heat-toxin swelling and pain from sores and ulcers. The *Shennong Bencao Jing* states it treats Xiao Ke (Wasting-Thirst), because by nourishing Yin and strengthening Water, thirst naturally ceases; it states it treats limb edema, because its cold and slippery nature promotes water passage, causing edema to subside; it states it benefits Qi, because by eliminating the excessive fire from food stagnation, Qi naturally benefits.

Mu Mu is originally not extremely cold nor extremely bitter. I have used it in equal parts with Huangqin (Scutellariae Radix), feeling no coolness or heat at all, indicating its nature is not severely cold. Furthermore, boiling one liang of Mu Mu with two qian of Gancao results in sweetness surpassing bitterness, indicating its taste is not severely bitter. Since neither its cold nor bitter properties are extreme, yet it is rich in fluids, it can nourish Yin. Some claim Mu Mu only reduces fever but cannot nourish Yin; this is a superficial understanding of Mu Mu. Therefore, when treating syndromes of heat excess with rapid pulse, I invariably use Mu Mu. In formulas using Huangqi (Astragali Radix) to tonify Qi, if I fear the patient's heat pathogen will reject the tonic, I often assist with Mu Mu. However, because its slippery fluid promotes bowel movements, it is contraindicated in patients with loose stools.

Tian Dong (Asparagi Radix): Sweet with slight pungency, cool in nature, with thick, slippery, and moistening juices. Its color is yellow mixed with white; entering the Lung, it clears dryness-heat, making it effective for resolving phlegm and calming coughs; entering the Stomach, it eliminates excess heat, making it effective for generating fluids and quenching thirst. Its thick and slippery nature promotes urination and defecation, circulates blood vessels, and unblocks meridians. Although it is a yin-nourishing substance, it actually also tonifies Qi. The statement in the *Shennong Bencao Jing* that "Tian Dong treats acute wind-dampness hemiplegia and strengthens bone marrow" has never been thoroughly explained by later commentators. I once chewed Tian Dong without residue, melting entirely into juice, and perceived an aroma resembling Renshen (Ginseng Radix et Rhizoma). This suggests that within its thick and slippery juices lies the vital energy of life. This energy, carrying the thick and slippery fluids, circulates throughout the body, removing wind-dampness hemiplegia affecting half the body, and nourishing bones throughout the body to strengthen bone marrow. The medicinal part is the root of Tian Dong, representing its internal aspect. Its external vines possess reverse thorns; if lacking thorns, the skin is rough and prickly. Tian Dong plants are inherently rigid outside and soft inside. As medicine, however, they contain rigidity within softness. Thus, wind-dampness bi syndrome encounters this "rigidity within softness," dispersing spontaneously without expectation. Bones receive this quality, not only strengthening bones but also marrow. The statements in the *Mingyi Bielu* that it "secures Lung Qi, benefits strength, and is cold yet tonifying" indeed reflect this understanding.

Appendix:
Letter from Cui XX of Tianmen County, Hubei Province:
I suffered from chronic cough unresponsive to various medicines. Later, taking one qian of Songzhi (Pini Resin) with cool tea cured the cough completely and improved my spirit. Upon reading the drug explanations in *Yixue Zhongzhong Canxi Lu*, learning that Tian Dong contains properties similar to Renshen, is rigid outside and soft inside, and has thick, moist juices, I switched to taking two qian of Tian Dong twice daily. For three years now, I feel refreshed and vigorous, with doubled strength, endurance for long journeys, smooth skin, and complete disappearance of facial scars.