五杂俎∶出弱水西，形如雀卵，色颇淡白，焚之辟邪去秽，鬼魅避之。情物志载汉武帝
焚西使香，宫中病者尽起。徐审得鹰嘴香，焚之，一家独不疫疾，即此类欤。
辟邪去疫，安魂魄，定惊悸。
出交趾、真腊、占城、琼海等处。单斗南云∶此乃伽 香树中空腹内所结，借伽 芬烈
之气
，得日月雨露之精凝结而成，故名气结。形亦同香块，而酥润松腻，不甚坚大，约伽 得其
质，此得其魂，亦如天生黄出汤泉，为硫气熏结而成者，然颇难得，世不多见。
治噎隔用一、二厘，酒磨服下，咽即开。
查浦辑闻∶海南人采香，夜宿香林下，望某树有光，即以斧斫之，记其处，晓乃伐取，
必得
美香。又见光从某树飞交某树，乃雌雄相感，亦斧痕记取之，得飞沉香，功用更大。
此香能和阴阳二气，可升可降。外达皮毛，内入骨髓，益血明目，活络舒筋。
方舆志∶生黎居五指山，山在琼州山中，所产有沉香，青桂香、鸡骨香、马蹄栈香，同
是一
本，其本颇类椿及榉柳，叶似桔，花白，子若槟榔，大如桑椹，交州人谓之蜜香。欲取者先
断其积年老根，经岁皮干朽烂，而木心与枝节不坏者，即香也。坚黑沉水者为沉香，细枝坚
实不烂者为青桂，半沉半浮者为鸡骨，形如马蹄者为马蹄，粗者为栈香。
*Wu Za Zu* records: It originates west of the Ruo River, shaped like a sparrow's egg, with a pale white color. Burning it expels evil and removes filth; ghosts and demons avoid it. *Qing Wu Zhi* records that Emperor Wu of Han burned incense presented by envoys from the Western Regions, and all patients in the palace recovered. Xu Shen obtained Yingzui Xiang (Eagle Beak Incense); after burning it, his family alone was spared from epidemic disease. This is likely the same type. [It has the functions of] expelling evil and preventing epidemics, calming the Hun and Po spirits, and stabilizing palpitations and fright.
It is produced in Jiaozhi, Zhenla, Zhancheng, Qionghai, and other places. Shan Dounan states: This forms within the hollows of the Qie Xiang tree (Aquilaria sinensis), condensing through the influence of the pungent fragrance of Qie Xiang and the essence of sun, moon, dew, and rain; hence it is named "Qi Jie" (Gas Knot). Its shape resembles incense blocks but is soft, moist, loose, and greasy, not particularly hard or large. Roughly speaking, Qie Xiang provides its substance, while this provides its spirit, similar to how natural sulfur forms from sulfur gas fumes in hot springs. However, it is rare and seldom seen in the world. For treating Yige (dysphagia/esophageal obstruction), use one or two li, grind with wine, and take orally; the throat will immediately open.
Cha Pu Jiwen records: People in Hainan collect incense by camping under incense forests at night. When they see light emanating from a certain tree, they chop it with an axe, mark the location, and harvest it at dawn, ensuring they obtain fine incense. They also observe light flying from one tree to another, indicating mutual attraction between male and female trees; they mark these with axe wounds to harvest Fei Chenxiang (Flying Agarwood), which has greater efficacy. This incense can harmonize Yin and Yang Qi, rising and descending as needed. It reaches the exterior skin and hair and penetrates the interior bone marrow; it benefits blood and brightens the eyes, activates collaterals, and relaxes tendons.
*Fang Yu Zhi* records: The Sheng Li people reside on Wuzhi Mountain, located in the mountains of Qiongzhou. The products include Chenxiang (Agarwood), Qinggui Xiang (Green Cinnamon Incense), Jigu Xiang (Chicken Bone Incense), and Matizhan Xiang (Horseshoe Stack Incense). All originate from the same tree. The trunk resembles Toona and Zelkova willow; leaves resemble citrus leaves; flowers are white; fruits resemble betel nuts, sized like mulberries. People in Jiaozhi call it Mixiang (Honey Incense). Those wishing to harvest it first cut off the old roots of accumulated age. After a year, the bark dries and rots, but the heartwood and branch joints remain unrotted; this is the incense. Hard, black, and water-sinking material is Chenxiang; fine branches that are solid and do not rot are Qinggui; half-sinking, half-floating material is Jigu; horseshoe-shaped material is Matixiang; coarse material is Zhanxiang.