五十难曰∶病有虚邪，有实邪，有贼邪，有微邪，有正邪，何以别之？然∶从后来者为虚邪，
从前来者为实邪，从所不胜来者为贼邪，从所胜来者为微邪，自病者为正邪。
何以言之？假令心病，中风得之为虚邪，伤暑得之为正邪，饮食劳倦得之为实邪，伤寒得之为微
邪，中湿得之为贼邪。
五十一难曰∶病有欲得温者，有欲得寒者，有欲得见人者，有不欲得见人者，而各不同，病在
何脏腑也？然∶病欲得寒，而欲见人者，病在腑也；病欲得温，而不欲见人者，病在脏也。何以言之？
腑者阳也，阳病欲得寒，又欲见人；脏者阴也，阴病欲得温，又欲闭户独处，恶闻人声。故以别知脏
腑之病也。
五十二难曰∶腑脏发病，根本等不？然∶不等也。其不等奈何？然∶脏病者，止而不移，其病不
离其处；腑病者，仿佛贲向，上下行流，居处无常。故以此知脏腑根本不同也。
五十三难曰∶经言七传者死，间脏者生，何谓也？然∶七传者，传其所胜也。间脏者，传其子
也。何以言之？假令心病传肺，肺传肝，肝传脾，脾传肾，肾传心，一脏不再伤，故言七传者死也。
假令心病传脾，脾传肺，肺传肾，肾传肝，肝传心，是子母相传，竟而复始，如环无端，故曰生也。
Chapter 50 states: Diseases include deficiency evil (Xu Xie), excess evil (Shi Xie), thief evil (Ze Xie), slight evil (Wei Xie), and correct evil (Zheng Xie). How are they distinguished? The answer is: Evil coming from the mother organ is deficiency evil; evil coming from the child organ is excess evil; evil coming from the organ that overcomes me is thief evil; evil coming from the organ that I overcome is slight evil; and disease originating from the organ itself is correct evil.
Why is this so? For example, in Heart disease, contracting wind pathogen results in deficiency evil; contracting summer-heat pathogen results in correct evil; injury from diet and fatigue results in excess evil; contracting cold pathogen results in slight evil; and contracting dampness pathogen results in thief evil.
Chapter 51 states: Some patients desire warmth, some desire cold; some wish to see people, some do not wish to see people. These manifestations differ. In which Zang or Fu organs are these diseases located? The answer is: Patients who desire cold and wish to see people have disease in the Fu organs; patients who desire warmth and do not wish to see people have disease in the Zang organs.
Why is this so? Fu organs belong to Yang. Yang diseases desire cold and wish to see people. Zang organs belong to Yin. Yin diseases desire warmth and wish to close doors and stay alone, disliking human voices. Thus, one can distinguish between Zang and Fu diseases based on these signs.
Chapter 52 states: Are the fundamental characteristics of disease onset in Zang and Fu organs the same? The answer is: No. How are they different? The answer is: Zang diseases are stationary and do not move; the pathology remains at its original location. Fu diseases are like running horses, flowing up and down, with no fixed location. Thus, one knows the fundamental difference between Zang and Fu diseases.
Chapter 53 states: The classic texts say, "Seven-transmission leads to death, intervening-Zang transmission leads to survival." What does this mean? The answer is: "Seven-transmission" refers to transmission to the organ it overcomes (Ke). "Intervening-Zang transmission" refers to transmission to its child organ.
Why is this so? Suppose Heart disease transmits to Lung, Lung to Liver, Liver to Spleen, Spleen to Kidney, and Kidney back to Heart. Each organ is injured only once and is not injured again. Therefore, it is said that "seven-transmission leads to death." Suppose Heart disease transmits to Spleen, Spleen to Lung, Lung to Kidney, Kidney to Liver, and Liver back to Heart. This is mother-child transmission, cycling endlessly like a ring without beginning or end. Therefore, it is said that "survival occurs."
Chapter 54 states: Zang diseases are difficult to treat, while Fu diseases are easy to treat. What does this mean? The answer is: Zang diseases are difficult to treat because they transmit to the organ they overcome (i.e., seven-transmission). Fu diseases are easy to treat because they transmit to their child organ (i.e., intervening-Zang transmission). This follows the same principle as seven-transmission and intervening-Zang transmission.