Lingshu-Yingwei Shenghui Chapter： "The middle energizer acts as a fermentor." "Fermentation" refers to the condition of the middle energizer digesting food and drink. "The middle energizer is like a pivot," indicating the digestive and transport functions of the spleen and stomach. The middle energizer, primarily the stomach, is responsible for digesting food and drink, absorbing the essence, and transforming body fluids, enabling nutrients to be distributed through the lung meridian to generate Yingqi. This process is likened to fermenting food to bring about transformation, hence the name.