In the land of Xing, one of the people's basic philosophies is that there exists a flow of life energy within the earth/All (signified by the mystical dragon), flowing metaphorically from the tops of mountains down to the land, nourishing everything it passes with that energy as does blood coursing through the veins. This energy is called the Dragon's Pulse (or Lung Mei). As such, this energy is prevalent in all things and breathes in rhythm with life forms.
Mei Chang, a master in Alkahestry, theorized something with this belief "Rather than stemming from the movement of tectonic plates in the Earth's crust, the true source of the alchemical energy is from the movement of a multitude of souls, which in turn form All, including the Universe." This allows others understanding better the Philosopher Stone's working and is related to the One is all, All is one creed.
While this philosophy is a central concept to the ancient Xingese art of Alkahestry, it can also be understood and manipulated by those who do not practice the craft: Royal warriors of Xing's fifty clans are taught to read the flow of the Dragon's Pulse, thereby becoming not only able to commune with nature and understand their surroundings, but sense the presence and movements of the people and animals around them by reading the pulse of natural energy within their bodies. It is with this power that the Xingese warriors Ling Yao, Lan Fan and Fu are able to sense the many spiritual anomalies in Central, including Alphonse Elric and the energy of the various Philosopher's Stones. The Ishvalan Scar has an array signifying the Dragon's Pulse tattooed on his right arm, mixing the Alchemical runes of Amestris and Xing with an Alkahestric source to allowing for unhindered transmutations.