四时温病，多似伤寒；伤寒起足太阳，今谓温病起手太阴，何以手太阴亦主外感乎？手太阴之
见证，何以大略似足太阳乎？手足有上下之分，阴阳有反正之义，庸可混乎！《素问·平人气象论》
曰∶脏真高于肺，以行营卫阴阳也。《伤寒论》中，分营分卫，言阴言阳，以外感初起，必由卫而营，由
阳而阴。足太阳如人家大门，由外以统内，主营卫阴阳；手太阴为华盖，三才之天，由上以统下，亦由
外以包内，亦主营卫阴阳，故大略相同也。大虽同而细终异，异者何？如太阳之窍主出，太阴之窍兼
主出入；太阳之窍开于下，太阴之窍开于上之类，学人须于同中求异，异中验同，同异互参，真诠自见。
前三焦篇所序之燥气，皆言化热伤津之证，治以辛甘微凉（金必克木，木受克，则子为母复仇，火
来胜复矣）未及寒化。盖燥气寒化，乃燥气之正，《素问》谓“阳明所至为清劲”是也。《素问》又谓“燥
急而泽”（土为金母，水为金子也）本论多类及于寒湿伏暑门中，如腹痛呕吐之类，经谓“燥淫所胜，民
病善呕，心胁痛不能转侧”者是也。治以苦温，《内经》治燥之正法也。前人有六气之中，惟燥不为病
之说。盖以燥统于寒（吴氏《素问》注云∶寒统燥湿，暑统风火，故云寒暑六入也），而近于寒，凡是燥
病，只以为寒，而不知其为燥也。合六气而观之，余俱主生，独燥主杀，岂不为病者乎！细读《素问》
自知。再前三篇原为温病而设，而类及于暑温、湿温，其于伏暑、湿温门中，尤必三致意者，盖以秋日
湿踞于内，新凉燥气加于外，燥湿兼至，最难界限清楚，稍不确当，其败坏不可胜言。经谓粗工治病，
湿证未已，燥证复起，盖谓此也（湿有兼热兼寒，暑有兼风兼燥，燥有寒化热化。先将暑湿燥分开，再
将寒热辨明、自有准的）。
四季的温病，大多与伤寒相似；但伤寒起于足太阳经，现在说温病起于手太阴经，为什么手太阴经也主管外感呢？手太阴经的表现症状，为什么大体上与足太阳经相似呢？手经与足经有上下之分，阴经与阳经有正反之义，怎么可以混淆呢！《素问·平人气象论》说：脏腑的真气高于肺，用来运行营卫和阴阳之气。《伤寒论》中，区分营分和卫分，谈论阴和阳，因为外感初起，必定由卫分进入营分，由阳分进入阴分。足太阳经就像人家的大门，从外部统领内部，主要主管营卫阴阳；手太阴经如同华盖（人体最高处的脏器，指肺），是三才中的天，从上统领下，也是从外部包裹内部，同样主要主管营卫阴阳，所以大体上相同。虽然大体相同但细节终究不同，不同之处在哪里呢？比如太阳经的孔窍主排出，太阴经的孔窍兼管出入；太阳经的孔窍开于下部，太阴经的孔窍开于上部等等，学习的人必须在相同中寻找不同，在不同中验证相同，将同与异互相参照，真正的真理自然显现。
前三焦篇所叙述的燥气，都是指化热伤津的症状，治疗用辛甘微凉的药物（金必克木，木受克制，则子为母复仇，火来胜复了）未涉及寒化。大概燥气的寒化，才是燥气的正常状态，《素问》所说的“阳明所至为清劲”就是指的这个。《素问》又说“燥急而泽”（土是金的母亲，水是金的儿子）本论多将其归类到寒湿伏暑门中，如腹痛呕吐等症状，经文所说“燥气淫盛，百姓生病善于呕吐，心胁痛不能转侧”就是指的这个。治疗用苦温药物，《内经》治疗燥气的正确方法。前人认为六气之中，只有燥气不致病。大概是因为燥气统属于寒（吴氏在《素问》注中说：寒统摄燥湿，暑统摄风火，所以说寒暑六入），而近于寒，凡是燥病，只把它当作寒，而不知道它是燥。综合六气来看，其余都主生，唯独燥主杀，难道不是致病因素吗！仔细研读《素问》自然知道。另外前三篇原本是为温病而设，却类及于暑温、湿温，对于伏暑、湿温门中，尤其必须再三注意的，大概是因为秋日湿气踞居体内，新凉的燥气加于体外，燥湿同时到来，最难界限清楚，稍微不恰当，其败坏后果不可胜言。经文说粗劣的医生治病，湿证还没好，燥证又起来，就是说的这种情况（湿有兼热兼寒，暑有兼风兼燥，燥有寒化热化。先将暑湿燥分开，再将寒热辨明，自有标准）。
Warm diseases in the four seasons are mostly similar to cold damage (Shanghan); however, while cold damage originates in the Foot-Taiyang channel (Foot-Taiyang Jing), it is now stated that warm diseases originate in the Hand-Taiyin channel (Hand-Taiyin Jing). Why does the Hand-Taiyin channel also govern external contraction? Why do the clinical manifestations of the Hand-Taiyin channel roughly resemble those of the Foot-Taiyang channel? There is a distinction between upper and lower for hand and foot channels, and a meaning of direct and reverse for yin and yang; how can they be confused! The *Suwen* (Plain Questions) · Pingren Qixiang Lun states: "The true qi of the zang organs is higher than the lung, which circulates Ying and Wei and yin and yang." In the *Shanghan Lun* (Treatise on Cold Damage), Ying and Wei are distinguished, and yin and yang are discussed, because at the initial stage of external contraction, one must necessarily proceed from Wei to Ying, and from Yang to Yin. The Foot-Taiyang channel is like the main gate of a house, governing the interior from the exterior, primarily managing Ying, Wei, yin, and yang; the Hand-Taiyin channel serves as the Huagai (Canopy, referring to the Lung as the highest organ), representing Heaven among the Three Powers, governing the lower from the upper, and also encompassing the interior from the exterior, similarly managing Ying, Wei, yin, and yang. Therefore, they are largely similar. Although largely similar, the details ultimately differ. What are the differences? For instance, the orifices of the Taiyang channel mainly govern excretion, whereas the orifices of the Taiyin channel govern both entry and exit; the orifices of the Taiyang channel open downwards, while those of the Taiyin channel open upwards, etc. Practitioners must seek differences within similarities, verify similarities within differences, and cross-reference sameness and difference, so that the true essence will naturally become apparent.
The dryness qi described in the previous three Jiao chapters all refer to syndromes where heat transformation injures fluids, treated with acrid-sweet slightly cool herbs (Metal overcomes Wood; when Wood is overcome, its son takes revenge for its mother, and Fire comes to restore balance). This did not cover cold transformation. Generally, the cold transformation of dryness qi represents the normal state of dryness, as stated in the *Suwen*: "What arrives via Yangming is clear and vigorous." The *Suwen* also states: "Dryness is urgent yet moist" (Earth is the mother of Metal, Water is the son of Metal). This treatise often categorizes such cases under the headings of latent damp-heat and cold-dampness, such as abdominal pain and vomiting. As the classics state: "When dryness qi prevails excessively, people suffer from frequent vomiting, heart and hypochondriac pain, and inability to turn their bodies." These are treated with bitter-warm methods, which is the correct method for treating dryness according to the *Neijing*. Previous scholars held the view that among the six qi, only dryness does not cause disease. This is likely because dryness is subsumed under cold (Wu's commentary on the *Suwen* states: Cold governs dryness and dampness, Summer-heat governs wind and fire, hence 'Cold and Summer-heat enter six'), and is close to cold. Thus, all dryness diseases were merely considered as cold, without recognizing them as dryness. Viewing the six qi collectively, all others govern life/growth, but dryness alone governs killing/destruction; could it not be a pathogenic factor? One would know this by carefully reading the *Suwen*. Furthermore, the previous three chapters were originally designed for warm diseases, yet they also include summer-heat warmth and damp-warmth. Special attention must be paid to the sections on latent summer-heat and damp-warmth, because in autumn, dampness resides internally while new cool dryness qi attacks externally. When dryness and dampness arrive simultaneously, it is most difficult to delineate clear boundaries. If the differentiation is slightly inaccurate, the disastrous consequences are incalculable. The classics state: "Incompetent physicians treat diseases; when dampness syndromes have not resolved, dryness syndromes arise again," which refers to this situation (Dampness may combine with heat or cold; Summer-heat may combine with wind or dryness; Dryness may undergo cold or heat transformation. First separate summer-heat, dampness, and dryness, then clearly differentiate cold and heat, and there will be a standard).