It turns out that this stone originated from the bottom of the sea, but it floated up from the sea. Some people say it's really health preservation, because Li Shizhen Ming really said in Compendium of Materia Medica that it "clears lung and purges fire, eliminates stagnation and removes old phlegm", which shows that this stone is a gift from the sea to mankind.
This kind of stone is pumice, with other names such as pumice, pumice and pumice. Because of its small specific gravity, it can float on the sea. There are two sources. One is the skeleton of the marine bryozoa, COLEOPTERA, commonly known as the stone flower; The other is a porous stone produced by volcanic eruption, also known as "pumice".
Both are called pumice, which are basically similar in shape, appearance and function. There is no distinction in ancient books, and there is no clear distinction sign in modern times, so they are often mixed, but the areas and methods of collection are different.
Stone flowers are mainly distributed in the coastal areas of Fujian, Zhejiang, Jiangsu and Guangdong. Because they naturally leave the attachments and float on the sea surface, they can't meet the demand, so they can be fished out of the seabed in autumn or summer, washed with water and dried in the sun.
Pumice are more common in Liaoning, Shandong, Fujian, Guangdong and other regions. Because numerous volcanic activities over thousands of years have caused a large number of pumice to be washed ashore, it is easier to collect. This pumice is attached to the coast by the sea. It only needs to be cut, soaked in clear water to remove salt, and then dried.
Most of pumice health preservation is based on its function of clearing lung-heat and resolving phlegm. There is also an introduction to pumice in Compendium of Materia Medica. The original text is "pumice removes phlegm and heat and overflows into the lungs". It can be seen that the health-preserving function of pumice lies in clearing away heat and resolving phlegm, and it is especially good at removing stubborn phlegm and old phlegm caused by lung heat.
If there is phlegm due to lung heat alone, you can use pumice to boil water for health preservation alone. Zhang Jingyue's "The Complete Book of Jingyue" in the Ming Dynasty recorded that pumice was cooked with Fritillaria, Arisaema cum bile and white mustard seed, clearing away heat and resolving phlegm, softening and resolving hard mass. Zhu Danxi, one of the four masters in Jin and Yuan Dynasties, recorded in Danxi Heart Method that water was boiled with pumice, gardenia, Fructus Trichosanthis and Qing Dynasty, which made liver fire flourish and affected lung phlegm.
Pumice has high health and medicinal value. In addition to clearing away heat and resolving phlegm, pumice can also soften and resolve carbuncle. Because lung is called "the source of water god", clearing lung fire can "clear a waterway", so pumice is used as medicine to induce diuresis and relieve stranguria.
However, it is worth noting that pumice is often used for health preservation because it can clear away lung heat and resolve phlegm, but it is cold in nature, so it is suitable for those with lung heat and phlegm heat, not for those with deficiency cold and phlegm heat. In addition, there is a medicinal material such as lichen and a succulent plant, also called stone flower, which needs to be distinguished.
Then pumice and Fructus Trichosanthis can eliminate phlegm, both are cold and can clear away heat, but their health is different. Pumice is good at removing old and stubborn phlegm, while Trichosanthes kirilowii is good at removing hot and dry phlegm.
After learning about pumice, people who see the boiled stone will know that it is health preservation. In addition to pumice, there are many mineral medicinal materials, such as purple and realgar. Lycium barbarum is not the only thing that can be soaked in a thermos cup for health preservation. What can be soaked is chosen according to everyone's physique.