(The Spleen and Stomach) rely on nourishment but fail to generate Kidney Water (Shui, 肾水). Since Water has no means to be generated, it cannot control Fire, causing the Fire of the Gate of Vitality (Mingmen, 命门) to become excessively hyperactive. The Fire of the Gate of Vitality is connected via a single meridian to the Pericardium (Xinbaoluo, 心包络). When the Fire of the Gate of Vitality is hyperactive, Heart Fire (Xinhuo, 心火) also becomes hyperactive. Between the chest and diaphragm, there is nothing but the blazing of Yin Fire (Yinhuo, 阴火). When Fire encroaches upon the Earth position (Spleen/Stomach), Metal (Lung) loses its function, and Fire subsequently overacts upon it. Therefore, when there is high-pitched breathing and panting, it is because Yin Qi fills and obstructs the Lung, making Lung Qi unfavorable. When there is body heat and vexation, it is because excessive Fire dries up Blood, leaving the Heart Spirit (Xinshen, 心神) without proper nourishment and peace, thus resulting in restlessness and vexatious heat. This is how diseases of Heart and Lung Qi manifest externally. Thus, whether it resembles Wind Strike (Shangfeng, 伤风) or Cold Damage (Shanghan, 伤寒), all are caused by insufficiency of Yang Qi (Yangqi, 阳气). If mistaken for an external contraction and treated with sweating methods, Lung Qi will become even more deficient; if treated with purgative methods, Yang Qi will sink downward. Mild cases often become severe, and severe cases often result in death. Therefore, Dongyuan’s *Differentiation between External Injury and Internal Injury* states: External injury constitutes excess; excess should be drained. Internal injury constitutes deficiency; deficiency should be tonified.