七情所病，谓之内伤；六淫所侵，谓之外感。自《内经》、《难经》以及唐宋诸书，无
不言
之深切着明矣。二者之病，有病形同而病因异者；亦有病因同而病形异者；又有全乎外感。
全乎内伤者；理会有内伤兼外感，外感兼内伤者。则因与病，又互相出入，参错杂乱，治法
迥殊。盖内伤由于神志，外感起于经络。轻重浅深，先后缓急，或分或合，一或有误，为害
非轻。能熟于《内经》及仲景诸书，细心体认，则虽其病万殊，其中条理井然，毫无疑似，
出入变化，无有不效。否则彷徨疑虑，杂药乱投，全无法纪，屡试不验。更无把握，不咎己
之审病不明，反咎药之治病不应。如此死者，医杀之耳！
病有一定之传变，有无定之传变。一定之传变，如伤寒太阳传阳明，及《金匮》见肝之
病，
知肝传脾之类。又如痞病变臌，血虚变浮肿之类，医者可预知而防之也。无定之传变，或其
人本体先有受伤之处，或天时不知，又感时行之气，或调理失宜更生他病，则无，病不可变
，医者不能预知而为防者也。总之人有一病，皆当加意谨慎，否则病后增病，则正虚而感益
重，轻病亦变危矣。至于既传之后，则标本缓急先后分合，用药必两处兼顾，而又不杂不乱
，则诸病亦可渐次乎复，否则新病日增，无所底止矣。至于药误之传变，又复多端，或过于
寒凉，而成寒中之病。或过服温燥，而成热中之病；或过于攻伐，而元气大虚；或过于滋润
，而脾气不实。不可胜举。近日害人最深者，大病之后，邪未全退，又不察病气所伤何处，
即用附子、肉桂、熟地、麦冬、人参、白术、五味、萸肉之类，将邪火尽行补涩，始若相安
，久之气逆痰升，胀满昏沉，如中风之状。邪气与元气相并，诸药无效而死。医家、病家犹
以为病后大虚所致。而不知乃邪气固结而然也。余见甚多，不可不深戒！
七情（喜、怒、忧、思、悲、恐、惊等情绪）致病，称为内伤；六淫（风、寒、暑、湿、燥、火等外邪）侵袭，称为外感。从《黄帝内经》、《难经》以及唐宋以来的各种医书来看，没有不将这两者阐述得深刻而明白的。这两种疾病，有症状表现相同但病因不同的；也有病因相同但症状表现不同的；还有完全是外感病或完全是内伤病的；按理说也会有内伤兼夹外感、外感兼夹内伤的情况。那么病因与病症之间，又互相交错，错综复杂，治疗方法截然不同。大概内伤源于神志（精神情志），外感起于经络（体表经脉）。在病情的轻重、深浅、先后、缓急方面，或是分开治疗或是合并治疗，一旦有一处出错，造成的危害就不轻。如果能熟读《黄帝内经》及张仲景等人的著作，细心体会和辨认，那么即使病情千变万化，其中的条理也是井然有序的，没有任何疑惑，灵活运用也不会无效。否则就会彷徨疑虑，胡乱投药，完全没有法度规矩，多次尝试都不见效。更加没有把握，不责怪自己诊断病情不明，反而责怪药物治病无效。像这样死去的病人，其实是医生害死的！
疾病有一定的传变规律，也有无固定规律的传变。一定的传变，比如伤寒病从太阳经传到阳明经，以及《金匮要略》中说的见到肝病，知道肝会传脾这类情况。又如痞证（心下痞塞不适）变成臌胀（腹部胀大如鼓），血虚变成浮肿这类情况，医生可以预先知晓并加以预防。无固定的传变，或者是患者本身体质先有受损之处，或者因天时变化不知晓，又感染了时行疫病之气，或者调理不当又生出其他疾病，那么这种病的变化，医生不能预先知晓并加以预防。总之人只要有一种病，都应当加意谨慎，否则病后增加新病，就会导致正气虚弱而感受的病邪更加严重，轻症也会变成危重症了。至于已经发生传变之后，对于标本、缓急、先后、分合的处理，用药必须两处兼顾，而且不乱不杂，那么各种疾病也可以逐渐恢复，否则新病日益增加，就没有止境了。至于因为用药错误导致的传变，又有多种端绪，或者过于使用寒凉药物，而成寒中之病；或者过服温燥药物，而成热中之病；或者过于攻伐，而导致元气大虚；或者过于滋润，而导致脾气不实。这种情况多得举不胜举。近年来害人最深的是，在大病之后，邪气尚未完全消退，又不察看病气损伤了身体的哪个部位，就立即使用附子、肉桂、熟地黄、麦冬、人参、白术、五味子、山茱萸之类的药物，将邪火全部用补涩的方法固摄住，起初似乎相安无事，久而久之导致气逆痰升，腹胀昏沉，呈现出类似中风的症状。邪气与元气相互搏结，各种药物都无效而死。医生和病家还以为是病后大虚所致，而不知道这是邪气固结造成的。我见到的很多，不可不深深引以为戒！
Diseases caused by the Seven Emotions (joy, anger, worry, thought, sadness, fear, and fright) are termed Internal Injury; invasions by the Six Excesses (wind, cold, summer-heat, dampness, dryness, and fire) are termed External Contraction. From the *Huangdi Neijing* (Yellow Emperor's Inner Canon), *Nan Jing* (Classic of Difficult Issues), and various medical texts from the Tang and Song dynasties onwards, there is no work that does not expound upon this clearly and profoundly. Regarding these two categories of disease, there are cases where the clinical manifestations are identical but the etiology differs; there are also cases where the etiology is the same but the clinical manifestations differ. Furthermore, there are conditions that are purely external contraction or purely internal injury. Logically, one must also consider cases of internal injury complicated by external contraction, or external contraction complicated by internal injury. Thus, etiology and pathology intersect and intermingle in a complex manner, requiring distinctly different treatment methods. Generally speaking, internal injury originates from the Shen (Spirit/Mind), while external contraction arises in the meridians (Jingluo). In terms of severity, depth, sequence, and urgency, whether treating separately or jointly, any error can lead to significant harm. If one is well-versed in the *Huangdi Neijing* and the works of Zhang Zhongjing, and carefully observes and discerns, then although diseases may present in myriad ways, their underlying principles remain orderly and clear, leaving no room for doubt; flexible application will yield effective results. Otherwise, one will hesitate and be uncertain, indiscriminately administering medicines without any methodological discipline, leading to repeated failures. Lacking confidence, instead of blaming oneself for unclear diagnosis, one blames the medicine for ineffectiveness. Those who die in such circumstances are killed by the physician!
Diseases have both fixed patterns of transmission and non-fixed patterns of transmission. Fixed patterns of transmission include, for example, the progression of Shanghan (Cold Damage) disease from the Taiyang meridian to the Yangming meridian, or as stated in the *Jingui Yaolue* (Essential Prescriptions of the Golden Cabinet), knowing that liver disease will transmit to the spleen. It also includes conditions like Pi syndrome (epigastric fullness/obstruction) transforming into Gu zhang (abdominal distension/tympanites), or blood deficiency transforming into edema; physicians can anticipate and prevent these. Non-fixed patterns of transmission occur when a patient has pre-existing constitutional weaknesses, or due to unknown climatic changes, they contract epidemic pathogens, or due to improper care, new illnesses arise. In such cases, the disease's evolution cannot be predicted or prevented by the physician. In summary, whenever a person has a disease, utmost caution must be exercised; otherwise, secondary complications may arise, weakening the Zheng Qi (Upright Qi) and making the pathogenic factor more severe, turning mild conditions into critical ones. After transmission has occurred, regarding the handling of Ben (Root/Etiology) and Biao (Branch/Symptoms), urgency, sequence, and separation or combination, medication must address multiple aspects simultaneously without confusion or杂乱ness; thus, various diseases can gradually recover. Otherwise, new diseases will increase daily without limit. As for transmission caused by medicinal errors, there are numerous variations: excessive use of cold-cooling herbs may result in Cold-Zhong disease; overuse of warm-drying herbs may result in Heat-Zhong disease; excessive purgation may severely deplete Yuan Qi (Original Qi); and excessive moistening may fail to strengthen Pi Qi (Spleen Qi). These instances are too numerous to list. In recent years, the most harmful practice occurs after major illnesses, when pathogens have not fully subsided. Without examining which part of the body's Qi has been injured, physicians immediately administer tonifying and astringent herbs such as Fuzi (Aconite Lateralis Radix Praeparata), Rougui (Cinnamomi Cortex), Shudi Huang (Rehmanniae Radix Preparata), Maidong (Ophiopogonis Tuber), Renshen (Ginseng Radix), Baizhu (Atractylodis Macrocephalae Rhizoma), Wuweizi (Schisandrae Fructus), and Yurou (Corni Fructus), thereby trapping the pathogenic fire through tonification and astringency. Initially, it may seem stable, but over time, it leads to rebellious Qi and rising Phlegm, abdominal distension, drowsiness, and symptoms resembling Stroke (Zhongfeng). The pathogen and Zheng Qi become entangled, rendering all medicines ineffective, leading to death. Physicians and patients still attribute this to post-illness severe deficiency, unaware that it is actually due to the consolidation of pathogenic factors. I have seen many such cases; this must be deeply cautioned against!