Library

This is the resin of *Haloxylon ammodendron* (Hu Tong Lei). Also known as Hu Tong Lv. "Lv" means "Li" (dripping/exudate), similar to how pine resin is referred to as asphalt. It is produced in the valleys and flat plains west of Suzhou.
It is also found in the western regions. The resin seeps into the soil, resembling alum or saltpeter. It is harvested in winter. There are two types: "Mu Lei" (Wood Weep) or "Mu Lv," which resembles paste or oil and is the exuded resin; and "Shi Lei" (Stone Weep) or "Shi Lv," which is resin that has penetrated between rocks and soil, forming blocks like flakes. Because it absorbs the qi of saline-alkali land, only its salty, bitter, and very cold properties are used in medicine. Its flavor and aroma are both strong, belonging to yin within yin. It enters the Foot Yangming Meridian. It mainly treats toothache caused by damp-heat, toothache due to wind-worms, gan disease (pediatric malnutrition syndrome), and gucao feng (osteomyelitis of the jaw).
A case was treated for a female patient suffering from ya gang (necrotizing gingivostomatitis), using five qian.

[Discussion] Hu Tong Lei is produced in extreme western regions. The tree's nature rises with the wind, yet it receives qi from cool and clear sources. Its sap seeps into the earth, further fermenting into salty and bitter flavors; this is the process of receiving qi through transformation.

[Differentiation and Treatment] Those shaped like small stone flakes and having a yellow-earth color are considered superior.

Also known as Feng Xiang Zhi (Liquidambar Resin). The leaves of this tree turn red after frost. It is abundant in the southern regions and Guan-Shaanxi areas. Flowers and fruits appear in February, resembling eggs. When ripe in August or September, they are burned to extract the resin, called Bai Jiao Xiang (White Glue Fragrance). Cuts are made in the bark in May to form channels, and harvesting occurs in November.
Its flavor is pungent, bitter, and neutral. It mainly treats hematemesis (vomiting blood), epistaxis (nosebleed), and hemoptysis (coughing up blood). It invigorates blood, generates flesh, and relieves pain. Its nature is unblocking and circulating. It treats all kinds of carbuncles, ulcers, sores, scabies, and traumatic injuries from metal weapons. After burning, it can be used to rub the teeth.
Treats tendons... [Text fragment/missing content]
All... pill treatment... for dissolution... for external use... for... one... [Text fragment/missing content]

[Discussion] Feng Zhi is pungent, corresponding to Metal. It is also bitter, corresponding to Fire. However, its neutral nature also corresponds to Metal. The leaves turning red after frost indicates Metal being utilized by Fire. Due to the transformation upon... [Text fragment]. Introducing fire into water, the resin harvested in mid-winter (the eleventh lunar month) is truly the divine mechanism for generating blood in the human body and an excellent substance for invigorating blood.
For chronic diarrhea and incessant abdominal pain, there is Nan Bai Jiao Xiang San (Southern White Glue Fragrance Powder), using Yu Mi Ke (Pericarpium Papaveris / Poppy Shell) as the sovereign herb, Long Gu (Fossilized Bones) and Jiao Xiang as minister herbs, and Gan Cao (Licorice Root) and Pao Jiang (Prepared Ginger) as assistant herbs. Is this using the transformation of yin to guard yang? Does it not go beyond merely invigorating blood?

[Differentiation and Treatment] Both Song Zhi (Pine Resin) and this resin can confuse Ru Xiang (Olibanum). However, Feng Xiang is slightly white-yellow in color, and burning it can reveal authenticity. Boil in vinegar solution for twenty boils, then add cold water... [Text cut off]