169、医书有一证示一治法，不言兼证也，尤不能言先作何证，后见何证也。故贵多读书，尤贵多临证。
170、士不谈五道，则樵夫笑之，何独于窍道而有道不谈道之说耶？
171、闭之与脱，截然两途。闭者邪气固束于外，元气安□在内。脱者邪气大伤其元，元气不就其邪。脱者泻之，气绝即死。闭者补之，邪锢而死。
172、病至舌黑、齿焦、唇裂，莫不以为燥，至于此自应纯用滋润药矣，而仲景于此只用厚朴、枳实之燥，大便一通，其燥即去，一用滋药，自此不再润矣。
173、《云笈七签》引《阴阳应象大论》：“冬伤于寒，春必病温”作“冬伤于汗，春必病温”。凡《内经》之言精，皆是言汗，此作“汗”字，正与《金匮真言》称“夫精者身之本也，故藏于精者，春不病温”。可以互证。而《评热论》所言，“汗者精气也，人所以汗出者，皆生于穀，穀生于精”者，不盖可见藏于精之为不妄出汗耶？喻嘉言读书未遍，固无怪其不知精之为汗也。
169. Medical texts often present a treatment method for a single symptom without mentioning concurrent syndromes; furthermore, they fail to elucidate the sequence of symptoms, i.e., which syndrome appears first and which follows later. Therefore, while it is valuable to read extensively, it is even more valuable to engage in clinical practice.
170. If a scholar does not discuss the "Five Paths" (referring to the five moral principles advocated by Confucianism or the proper ways of life), he will be laughed at by woodcutters. Why, then, should there be a notion of not discussing the "Dao" (the Way/principles) concerning the "Qiao Dao" (the physiological and pathological principles of body orifices)?
171. "Bi" (Obstruction/Closure) and "Tuo" (Collapse/Exhaustion) are two completely distinct pathways. In "Bi" syndrome, pathogenic factors are firmly bound externally, while the Yuan Qi (Original Qi) remains secure internally. In "Tuo" syndrome, pathogenic factors severely damage the Yuan Qi, causing the Yuan Qi to detach from its anchor and collapse outward. Applying purgative methods to "Tuo" syndrome leads to immediate death due to Qi exhaustion; applying tonifying methods to "Bi" syndrome results in death due to the entrapment of pathogenic factors.
172. When a disease progresses to black tongue coating, scorched teeth, and cracked lips, it is universally regarded as Dryness-Heat. At this stage, one should theoretically use purely moistening herbs. However, Zhang Zhongjing used only drying herbs such as Houpo (Magnolia Bark) and Zhishi (Immature Bitter Orange). Once the stool was unblocked, the dryness resolved. If moistening herbs had been used instead, the bowels would never have moved smoothly again.
173. The *Yunji Qiqian* cites the *Yin Yang Ying Xiang Da Lun* (Great Treatise on the Correspondence of Yin and Yang), rendering "Winter injury by Cold leads to Warm diseases in Spring" as "Winter injury by Sweat leads to Warm diseases in Spring." All references to "Jing" (Essence) in the *Nei Jing* (Inner Canon) actually refer to "Sweat." The use of the character "Sweat" here corroborates the statement in the *Jin Gui Zhen Yan Lun* (True Words of the Golden Cabinet): "Jing is the root of the body; therefore, those who preserve their Jing will not suffer from Warm diseases in Spring." Furthermore, the *Ping Re Lun* (Discussion on Fever) states: "Sweat is Essence-Qi; the reason humans sweat is that it originates from Grain, and Grain originates from Jing." Does this not demonstrate that preserving Jing prevents reckless sweating? Yu Jiayan did not read widely enough, so it is no wonder he did not understand that Jing refers to Sweat.