Shizhongru (Stalactite), growing in the valleys of Mount Shaoshi and Mount Tai, is now also found in the mountains of Jianghua County in Daozhou, as well as in Lianzhou, Yingzhou, Shaozhou, Jiezhou, and Xiazhou. Those growing in the shade of rock caves without "goose-tooth" textures and possessing a bright luster are of superior quality. The color is white with a slight red tint, and it can be harvested at any time. Old texts state there are three types of milk-like minerals: Stone Milk (Shiru) grows on pure stone mountains, nourished by mineral seepage from the rocks; shaped like cicada wings, its nature is warm; Bamboo Milk (Zhuru) grows on mountains abundant in bamboo, nourished by bamboo sap; shaped like bamboo shoots, its nature is neutral; and Maoshan Milk grows on mountains where earth and stone mix with abundant thatch grass, nourished by grass sap; slightly black and smooth in texture, its nature is slightly cold. These three types are particularly difficult to distinguish. Li Buchuo of the Tang Dynasty described a method for refining Stalactite: select Stalactite from Shaozhou, regardless of thickness, provided the color is clear and lustrous, which is suitable for refining; only yellow and reddish varieties are unusable. In his "Letter to Cui, Prefect of Lianzhou on Stalactite," Liu Zongyuan also stated that one should select based on aesthetic color alone, not necessarily relying solely on soil origin. Thus, the key criterion for this medicine is clarity and purity, rather than strictly adhering to the aforementioned categories. Current physicians consider those hollow like goose tubes to be the best. Additionally, the *Shennong Bencao Jing* (Divine Farmer's Materia Medica), Middle Category, records Yinnie (Yin Nodule): it is the root of Stalactite, growing in the valleys of Zhao State, as well as in Liangshan and Nanhai. It further states: Konggongnie (Konggong Nodule) is the root of Yinnie, growing in the valleys of Liangshan. It also notes: Shihua (Stone Flower) and Shichuang (Stone Bed) are of the same category as Yinnie. Tao Hongjing stated: All Stalactite-related substances belong to one body. The substance formed by long-term accumulation and coagulation of drippings from the ceiling of stone chambers is called Zhongru Chuang (Stalactite Bed), which is the Konggongnie mentioned here; the smaller ones below it are called Yinnie, currently referred to as Konggongnie by people. When Yinnie flows again and becomes light and fine, it transforms into Stalactite. Although they are of the same class, their therapeutic properties differ. Su Gong stated: The two nodules are located above, while beds and flowers are below; Tao Hongjing’s claim that Konggongnie is the milk bed is incorrect. There is also Shinao (Stone Brain), which is also a type of Stalactite. Of these five types, current physicians rarely use them, employing only Stalactite. Observing that the two nodules originate from different prefectures, and considering Tao Hongjing’s assertion that the three share the same root but appear in various places, it seems their quality varies according to local conditions. Since they are said to grow together with Stalactite, wherever nodules exist, Stalactite should also be present; yet such occurrences are rarely heard of today. Is it because low usage leads to scarce harvesting? Or do contemporary practitioners fail to recognize Stalactite within the nodules, thus failing to harvest them fully? This cannot be thoroughly investigated. The Lower Category also includes Tuyinnie (Earth Yin Nodule). The Classic states: it grows in the shaded areas of high mountain cliffs, white in color like fat. Tao Hongjing considered it a type of Stalactite or Konggongnie. Su Gong stated: It is Earth Milk (Turu), produced in Weizhou, growing in earthen caves on flat land. Locals say: taking it has similar effects to Stalactite but does not cause fever. They also add: it is the lipid fluid of the earth, resembling Yinnie in shape, hence the name. It is no longer used today.