两感有三。有阴阳两感。有脏腑两感。有寒温两感。阴阳两感者阴阳两经。并感于寒毒也。素问灵枢所说两感。
并是此义。此有故。寒先伏于下焦。新寒复中于上焦。上下两邪相引。故邪由阴道而上冲。新邪由阳道而内入。亦
有同时并感者。必由薄衣露处。及冒寒远行。劳力汗出。邪气乘虚而入。此时邪气。直是漫天盖地而来。何暇辗转
传经。由浅渐进。又何暇阴阳匀配。范我驰驱哉。故太阳少阴两病。未必不兼见阳明太阴证。阳明太阴两病。未必
不兼见少阳厥阴证。然邪气究须有从入之先道。细审机括。亦自有孰正孰兼孰重孰轻之辨。
脏腑两感者。外经与脏腑。同感于寒毒。非传腑传脏之谓也。此或由饮食伤于肠胃。或由呼吸入于膻中。故小
儿当风饮食。当风啼哭。极宜慎之。外既感受风寒。而又内寒上冲于肺下侵于肾。于是恶寒发热。筋骨强痛之中。
又有咳嗽呕吐泻泄腹痛之苦。仲景先救其里。后攻其表。是缓治也。急者温中发表并用。风扰于中。其势极恶。霍
乱转筋。非桂不足以制之。
寒温两感者。寒温两毒相伏。非伤寒化温。温病转寒之谓也。外邪所伤谓之毒。内气所化。不得谓之毒。即不
得谓之两感伤寒有初起即见寒死证。无初起即见热死证。其有热死者。日久失治也。否则先有温邪内伏也。温病有
初起即见热死证。无初起即见寒死证。其有寒死者。日久失治也。否则先有寒邪下伏也。常有秋月久晴燥邪由呼吸
伏于膻中。霜降以后。天气乍寒。腠理开豁。邪气乘之。其证寒热强痛。而初起即神识昏迷。谵语气粗。口渴索水。
又有夏月伏暑。为秋凉所遏。不得发越。入冬感寒而发病者。其证胸中烦热。如破皮状两足如冰入夜转热如焚。烦
躁不能安眠。此暑毒在血之故。又有冬月寒伏下焦。入春感于风温而发病者。其证初起上见喘粗。声如瓮中。渐见
面目 肿。神识昏迷反胃干呕也。大法先治其温。后治其寒。与真寒假热。真热假寒诸治法不同。
两感证有三种情况。一是阴阳两经同时受邪，二是脏腑同时受邪，三是寒邪与温邪同时受邪。所谓阴阳两感，是指阴经和阳经同时感受寒毒。《素问》和《灵枢》中所说的“两感”，都是这个意思。这种情况的成因是：旧有的寒邪先潜伏在下焦，新的寒邪又侵袭上焦，上下两种邪气相互牵引，所以邪气从阴分向上冲逆，新邪从阳分向内侵入。也有新旧邪气同时感受的情况。这必定是因为穿着单薄暴露在外，或者冒寒远行，劳累用力后出汗，导致邪气乘虚而入。此时的邪气，铺天盖地而来，哪里还有时间慢慢传变经络、由浅入深？哪里还有时间阴阳均匀配合、遵循常规的治疗规律呢？因此，太阳病和少阴病同时发病时，未必不兼见阳明病和太阴病的证候；阳明病和太阴病同时发病时，未必不兼见少阳病和厥阴病的证候。然而，邪气终究需要有入侵的途径，仔细审察其机理，自然有正气与兼证、病情轻重缓急的辨别。
所谓脏腑两感，是指体表经络与内脏同时感受寒毒，并不是指病邪由腑传脏或由脏传腑的意思。这可能是由于饮食损伤了肠胃，或者呼吸使邪气进入膻中（胸中）。所以小儿在风中饮食、在风中啼哭，都极需谨慎防范。体表既感受了风寒，内里的寒邪又上冲于肺、下侵于肾，于是在恶寒发热、筋骨强痛之中，又加上咳嗽、呕吐、腹泻、腹痛的痛苦。张仲景主张先救里证，后解表证，这是缓治的方法。急症则需温中散寒与发表解表并用。风邪扰乱中焦，病情极其凶险，出现霍乱、转筋等症状，非用桂枝等药不足以制约它。
所谓寒温两感，是指寒邪与温邪两种毒气同时潜伏体内，并不是指伤寒转化为温病，或温病转化为伤寒的意思。外来的邪气伤害人体称为“毒”，体内的气化变化产生的热，不能称为“毒”。既然不能称为两感，那么伤寒初起就有因寒而死的证候，却没有初起就因热而死的证候。那些初起就因热而死的，是因为日久失治，或者是先前已有温邪潜伏体内。温病初起就有因热而死的证候，却没有初起就因寒而死的证候。那些初起就因寒而死的，是因为日久失治，或者是先前已有寒邪潜伏在下焦。常有这样的情况：秋季久晴，燥邪通过呼吸潜伏在膻中，霜降以后，天气突然变冷，腠理开泄，邪气乘虚而入，表现为寒热交作、剧烈疼痛，且初起就出现神识昏迷、说胡话、声音粗重、口渴想喝水的症状。又有夏季伏暑，被秋季凉气遏制，不得发散，到了冬季感受寒邪而发病的，表现为胸中烦热，像皮肤破损一样难受，两脚冰凉，入夜后身体转热如火，烦躁不能安眠，这是暑毒在血分的缘故。又有冬季寒邪潜伏在下焦，到春季感受风温而发病的，表现为初起上部气喘粗重，声音像瓮中发声，逐渐出现面目浮肿、神识昏迷、反胃干呕等症状。治疗的大法是先用治温病的方法，后用治寒邪的方法，这与真寒假热、真热假寒等各种治法不同。
There are three types of "Liang Gan" (simultaneous infection of yin and yang channels or organs). One is the simultaneous infection of yin and yang channels; another is the simultaneous infection of zang and fu organs; the third is the simultaneous infection of cold and warm pathogens. The so-called simultaneous infection of yin and yang refers to both yin and yang channels simultaneously contracting cold pathogenic factors. What is described as "Liang Gan" in the *Suwen* (Basic Questions) and *Lingshu* (Spiritual Pivot) all refer to this meaning. The etiology of this condition is that latent old cold first resides in the Lower Jiao (lower burner), and new cold subsequently attacks the Upper Jiao (upper burner). The two evils from above and below attract each other, causing the pathogen to rush upward from the Yin aspect, while the new pathogen enters inward from the Yang aspect. There are also cases where both pathogens are contracted simultaneously. This must result from wearing thin clothes and being exposed to the elements, or traveling far in the cold, leading to sweating after physical exertion, allowing the pathogen to enter through deficiency. At this time, the pathogen comes overwhelming like a blanket covering heaven and earth. How could there be time for gradual transmission through the meridians, progressing from shallow to deep? How could there be time for balanced yin-yang coordination or adherence to standard treatment protocols? Therefore, when Taiyang disease (Taiyang channel syndrome) and Shaoyin disease (Shaoyin channel syndrome) occur together, they may not fail to present with symptoms of Yangming disease (Yangming channel syndrome) and Taiyin disease (Taiyin channel syndrome). When Yangming disease and Taiyin disease occur together, they may not fail to present with symptoms of Shaoyang disease (Shaoyang channel syndrome) and Jueyin disease (Jueyin channel syndrome). However, the pathogen ultimately requires an entry route. Careful examination of the mechanism reveals distinctions between primary and secondary conditions, and between severe and mild presentations.
The so-called simultaneous infection of zang and fu organs refers to the simultaneous contraction of cold pathogenic factors by the exterior meridians and the internal organs, not referring to the transmission of disease from fu organs to zang organs or vice versa. This may arise from dietary injury to the stomach and intestines, or from respiration allowing pathogens to enter the Danzhong (Chest Center/Shanzhong). Therefore, one must be extremely cautious regarding children eating or crying in the wind. If the exterior is affected by wind-cold, and internal cold rushes upward to the Lung (Lung) and downward invades the Kidney (Kidney), then amidst aversion to cold, fever, and stiffness/pain of bones and sinews, there is added suffering from cough, vomiting, diarrhea, and abdominal pain. Zhang Zhongjing advocated treating the interior first and then attacking the exterior, which is a method of slow treatment. For acute cases, warming the middle and releasing the exterior are used simultaneously. Wind disturbing the middle causes extremely severe conditions, such as Huoluan (cholera-like disorder with vomiting and diarrhea) and tendon retraction (cramps/spasms); only Guizhi Tang (Cinnamon Twig Decoction) or similar agents containing Cinnamon Twig are sufficient to control it.
The so-called simultaneous infection of cold and warm refers to the co-latency of cold and warm toxic pathogens, not referring to Shanghan (Cold Damage) transforming into Wenbing (Warm Disease), or Wenbing turning into cold. External pathogens harming the body are called "toxic," whereas heat generated by internal Qi transformation cannot be called "toxic." Since it cannot be called simultaneous infection, Shanghan may present with fatal cold syndromes at onset, but never fatal heat syndromes at onset. Those who die of heat at onset do so due to prolonged neglect of treatment or because warm pathogens were already latent internally. Conversely, Wenbing may present with fatal heat syndromes at onset, but never fatal cold syndromes at onset. Those who die of cold at onset do so due to prolonged neglect of treatment or because cold pathogens were already latent in the Lower Jiao. A common scenario involves dryness pathogen, resulting from long sunny periods in autumn, lying latent in the Danzhong via respiration. After Frost's Descent, when weather suddenly turns cold and pores open, the pathogen takes advantage, presenting with alternating chills and fever, severe pain, and initial confusion/coma, delirium, coarse voice, and thirst craving water. Another scenario involves summerheat latent in summer, suppressed by autumn coolness, unable to vent, and manifesting in winter after contracting cold. Symptoms include vexatious heat in the chest, feeling like broken skin, ice-cold feet, and night-time feverish heat like burning, with restlessness and insomnia; this is due to summerheat toxicity in the Blood level. Yet another scenario involves cold latent in the Lower Jiao during winter, manifesting in spring after contracting wind-warmth. Symptoms begin with upper respiratory distress, coarse breathing sounding like a pot, gradually progressing to facial/ocular edema, coma, regurgitation, and dry retching. The general principle is to treat the warm component first, then the cold component, which differs from treatments for true cold/false heat or true heat/false cold patterns.