"Liuqi Ganzheng Yaoyi," a specialized book on external contraction diseases, was written by Zhou Yan in 1898 during the Qing Dynasty. The author posits that the causes of external contraction diseases are confined to the six qi: wind, cold, summer heat, dampness, dryness, and fire. Accordingly, the text sequentially discusses various disease patterns including wind, apoplexy, cold, cold in the middle, summer heat, wind-warmth, dampness, wind-dampness, dampness warm disease, dryness, and fire. For each external contraction disease related to the six qi, the book first compiles theories, followed by explanations of prescriptions, gathering various scholarly opinions and incorporating personal insights to elucidate symptoms, causes, pulse diagnosis, and treatments. The work is available in editions such as the "Zhenben Yishu Jicheng" (Collection of Rare Medical Books).