Symbolic illustration of the kidneys. One of a set of five illustrations of internal organs from Uibang-yuchwi (Classified Collection of Medical Recipes), section on the Five Viscera.
Uibang-yuchwi is a compendium Yifang leiju -- or Chinese, Yifang leiju -- is a compendium of Chinese medical remedy literature compiled in C.15 Korea by Kim Rye-mong (1406-1469), Yu Seong-won (?- 1456) et al., under the auspices of King Sejong of Korea (r. 1418-1450). It originally comprised 365 juan (volumes), and contained over 50,000 precriptions drawn from 150 medical works ranging from the Qin period (221-206 BCE) to the early Ming (1368-1644). The original text is no longer extant. This image comes from a Japanese facsimile made in 1861 (1st year of the Bunkyu era), which unfortunately lacks juan 155, 156, 09 and 220.
The text says: Kidney: Qi of kan (Water), essence of Water. Its colour is black. It looks like a suspended stone. Its spirit has the form of a white deer. On both sides it engenders zhi knowledge, which is transformed into a Jade Child. It is 1 chi tall (1 chi [Chinese foot] = c. 1/3 m). It goes in and out of the treasure-house of the kidney.