Library

(From *Tang Bencao*)

[Names] Qingyang (from *Bencao Gangmu*), Puliú (from *Erya*), Puyang (from *Gujin Zhu*), Pu (pronounced "yi"), [ ] Liu (from *Gujin Zhu*).
Li Shizhen stated: The branches of the Yang tree are hard and rise upward, hence it is called "Yang". It grows abundantly in places with water reeds (*Pu*) and cattails (*Huan*), thus having names such as Shuiyang (Water Yang), Puliú (Reed Willow), and Huafu.

[Collected Explanations] Su Gong said: The leaves of Shuiyang (Water Poplar/Willow) are round, broad, and pointed at the tip; its branches are short and hard, completely different from true willows. True willow leaves are narrow and long, with long, slender, and soft branches.
Su Song said: *Erya* records: "Yang is Puliú." Its branches are strong and tough, suitable for making arrow shafts. The "Fu" mentioned in *Zuo Zhuan* refers to this. It grows abundantly in the sandy lands of Hebei today. There are many varieties of Yang and Liu trees. Cui Bao in *Gujin Zhu* stated: Baiyang (White Yang) has round leaves, Qingyang (Green Yang) has longer leaves, willow leaves are long and fine, and [ ] yang leaves are round and weak. The wood grain of Shuiyang is also reddish. However, people nowadays rarely distinguish between these categories.
Its flowers are the same as those of willows.

[Flavor and Properties] Bitter, neutral, non-toxic.

[Indications] Treats chronic dysentery with red and white pus/blood. Crush and extract one sheng (approx. 200ml) of juice and take it twice daily; it is highly effective (from *Tang Bencao*).
Treats carbuncles and sores (Yongzhong) and smallpox toxins (Li Shizhen).

[Elucidation] Li Shizhen said: The root of Shuiyang cures carbuncles, therefore modern practitioners use its branches and leaves to treat smallpox. Wei Zhi in *Boxiao Xinjian* stated: When smallpox lesions have been sunken for several days, the pus fails to form or move, or when blocked by wind-cold pathogenic factors. It is appropriate to use five jin (approx. 3kg) of Shuiyang branches and leaves (use branches if no leaves are available) and decoct them in a large pot of running water for a warm bath. If the water cools, add hot water. After a while, observe: if the lesions rise and show a halo, the pus is circulating. If not full, bathe again. For those with weak constitution, only wash the head, face, hands, and feet. If repeated bathing does not cause the lesions to rise, the qi and blood are exhausted, and further bathing is contraindicated. Bathing is contraindicated when the rash first appears or when it is itchy and collapsed.
Smallpox failing to generate pus is due to stagnant qi and blood, tight interstices (couli), or external obstruction by wind-cold. Bathing allows warmth to penetrate, harmonizing and unblocking stagnation, allowing qi and blood to flow freely. The pus forms and fills with the release of warmth, which is a significant effect. If internal medicines that tonify qi and blood are taken concurrently, the efficacy is accelerated, and wind-cold cannot obstruct it. Wei Zhi witnessed an old woman in a village using this method successfully. Upon inquiring about the prescription, he found it to be infallible. Do not alter it lightly; it truly possesses the subtle art of regulating harmony. Just as the movement of the Huangzhong pitch-pipe awakens hibernating insects, and the east wind melts hard ice, both represent the vitality of spring. This method is not recorded in other books, so I have detailed it here.

Bark of the Wood and Roots
[Flavor and Properties] Same as the branches and leaves.

[Indications] Pain from metal wounds (Jinchuang), mastitis (Ruyong) and other swellings, smallpox (Li Shizhen).

[Elucidation] Li Shizhen said: According to Li Zhongnan's *Yonglei Qianfang*: Someone treated mastitis by holding a single root, chewing it raw, and applying it to the sore. It felt hot like fire, and upon reapplication, the swelling subsided. Inquiring about the prescription, it was revealed to be the root of Shuiyang liu (Poplar/Willow). Ge Hong's *Zhouhou Beiji Fang* uses willow root to treat mastitis. Thus, the properties of Yang and Liu are similar and they can be used interchangeably.

[Attached Prescriptions] One new prescription.
Pain from metal wounds: Take the white inner bark of Yang wood, dry it by roasting, and grind into powder. Take one fangcun bi (approx. 5-10g) with water, and apply externally. Repeat three times daily. (From *Qianjin Fang*)