伤寒一日。足太阳受病。太阳者。膀胱之经也。为三阳之首。故受病。其脉络于腰脊。
主于头项。故得病一日。头项腰脊痛也。伤寒二日。足阳明受病。阳明者。胃之经也。主于
肌肉。其脉络于鼻。入于目。故得病二日。内热鼻干。不得眠也。诸阳在表。表始受病在皮
肤之间。故可摩膏、火灸、发汗而愈也。凡五脏不和。六腑不通。营卫不行。如是之后。
三日乃死。何也。夫足阳明者。胃之脉也。十二经之长也。其气血盛。故不通。三日其气乃
尽。故死尔。其未满三日者。可汗而已。其满三日者。可下而已也。伤寒三日。足少阳受病
。少阳者。胆之经也。其脉循于胁。上于颈耳。故得病三日。胸胁热而耳聋也。三阳经络。
始相传病。未入于脏。可汗而解也。伤寒四日。足太阴受病。太阴者。脾之经也。为三阴之
首。是故三日以后。阳受病讫。传之于阴。而太阴受病焉。其脉络于脾。主于喉嗌。故得病
四日。腹满而嗌干。其病在胸膈。故可吐而愈也。伤寒五日。足少阴受病。少阴者。肾之经
也。其经贯肾络肺。系于舌。故得病五日。口燥舌干。渴而引水也。其病在肠。故可下而愈
也。伤寒六日。足厥阴受病。厥阴者。肝之经也。其脉循阴络于肝。故得病六日。烦满而阴
缩也。此则阴阳俱受病。毒瓦斯在胃。可下而愈也。七日太阳病衰。头痛小愈。又伤寒七日。
病法当小愈。阴阳诸经传病终故也。今七日以后。病反甚者。欲为再经病也。再经病者。经
络重受病也。伤寒八日。阳明病衰。身热小愈。又八日不解者。或者诸阴阳经络。重受于病
。或因发汗吐下之后。毒瓦斯未尽。所以病证犹在也。伤寒九日。少阳病衰。耳聋微闻。又伤
寒九日以上。病不除者。或初一经受病者。不能相传。或已传三阳讫。而不能传于阴。致停
滞累日。病证不解。故日数多。而病候改变也。伤寒十日。太阴病衰。腹胃如故。则思欲饮
食。伤寒十一日。少阴病衰。渴止不烦满。舌干已也。伤寒十二日。厥阴病衰。囊少纵。腹
微下。毒瓦斯皆去。病日已矣。
伤寒第一天，足太阳经受邪。太阳经，是膀胱的经脉，为三阳经之首，所以受邪后，其脉络联系腰部脊柱，主管头部和项部。因此患病第一天，会出现头项部和腰脊部的疼痛。
伤寒第二天，足阳明经受邪。阳明经，是胃的经脉，主管肌肉，其脉络联系鼻部，进入眼部。因此患病第二天，会出现体内发热、鼻干、无法安睡的症状。
所有的阳经都在体表，体表刚开始受邪是在皮肤之间，所以可以用涂摩药膏、火灸、发汗的方法治愈。凡是五脏功能不和，六腑气机不通，营卫之气运行不畅，到了这种情况之后，三天就会死亡。为什么呢？因为足阳明经，是胃的经脉，也是十二经脉之长，它的气血旺盛，如果这里不通，三天后它的气血才会耗尽，所以就会死亡。病程未满三天的，可以通过发汗法治愈；病程已满三天的，可以通过泻下法治愈。
伤寒第三天，足少阳经受邪。少阳经，是胆的经脉，其脉循行于胁肋，上行至颈部和耳部。因此患病第三天，会出现胸胁部发热和耳聋的症状。三阳经的经络，开始相互传变致病，病邪尚未入脏，可以通过发汗法解除。
伤寒第四天，足太阴经受邪。太阴经，是脾的经脉，为三阴经之首。所以三天以后，阳经受邪完毕，病邪传入阴经，太阴经受邪。其脉络联系脾脏，主管咽喉。因此患病第四天，会出现腹部胀满和咽喉干燥的症状。病位在胸膈，所以可以通过催吐法治愈。
伤寒第五天，足少阴经受邪。少阴经，是肾的经脉，其经脉贯穿肾脏，联络肺脏，系连舌根。因此患病第五天，会出现口燥舌干、口渴想喝水的症状。病位在肠道，所以可以通过泻下法治愈。
伤寒第六天，足厥阴经受邪。厥阴经，是肝的经脉，其脉循行阴络联系肝脏。因此患病第六天，会出现心烦腹满和阴囊收缩的症状。此时阴阳两经都受邪，毒热之气在胃，可以通过泻下法治愈。
第七天，太阳病衰退，头痛轻微好转。另外，按照伤寒的规律，七天时病情应当轻微好转，这是因为阴阳各经的病邪传变已经终结的缘故。如果在七天以后，病情反而加重，这是想要发生“再经病”（病邪再次传遍一经）。所谓再经病，是指经络再次受邪。
伤寒第八天，阳明病衰退，身体发热轻微好转。如果八天后病仍未解，可能是诸阴阳经络再次受邪，或者是因为经过发汗、催吐、泻下治疗后，毒热之气未尽，所以病症仍然存在。
伤寒第九天，少阳病衰退，耳聋症状轻微减轻，能听到一点声音。另外，如果伤寒九日以上，病邪未除，可能是因为最初一经受邪后，不能继续传变，或者已经传遍三阳经，但不能传入阴经，导致病邪停滞多日，病症不解除，所以天数增多，而病症表现发生改变。
On the first day of *Shanghan* (Cold Damage), the Foot-Taiyang channel is affected. The Taiyang channel belongs to the Bladder, and is the head of the three Yang channels; therefore, upon being affected, its collaterals connect to the lumbar spine, and it governs the head and neck. Thus, on the first day of illness, there is pain in the head, neck, lumbar region, and spine.
On the second day, the Foot-Yangming channel is affected. The Yangming channel belongs to the Stomach, governs the muscles, and its collaterals connect to the nose and enter the eyes. Thus, on the second day of illness, there is internal heat, dryness of the nose, and inability to sleep.
All Yang channels are located at the exterior. When the exterior is initially affected, the pathogen resides between the skin and hair; thus, it can be cured by applying medicated oils, moxibustion, or inducing sweating. If the Five Zang organs are disordered, the Six Fu organs are obstructed, and the Ying (Nutritive) and Wei (Defensive) Qi fail to circulate properly, death will occur after three days. Why? Because the Foot-Yangming channel is the channel of the Stomach and the leader of the twelve channels; its Qi and Blood are abundant. If obstruction occurs here, it takes three days for this Qi to exhaust, leading to death. For illnesses not yet reaching three days, treatment by sweating is appropriate; for illnesses exceeding three days, treatment by purgation is appropriate.
On the third day, the Foot-Shaoyang channel is affected. The Shaoyang channel belongs to the Gallbladder, and its vessel courses along the hypochondrium, ascending to the neck and ears. Thus, on the third day of illness, there is heat in the chest and hypochondrium, and deafness. The meridians of the three Yang channels begin to transmit the disease among themselves, but the pathogen has not yet entered the Zang organs; it can be resolved by inducing sweating.
On the fourth day, the Foot-Taiyin channel is affected. The Taiyin channel belongs to the Spleen and is the head of the three Yin channels. Therefore, after the third day, when the Yang channels have finished receiving the pathogen, it transmits to the Yin channels, affecting the Taiyin. Its collaterals connect to the Spleen, and it governs the throat. Thus, on the fourth day of illness, there is abdominal fullness and dryness of the throat. Since the disease is located in the chest and diaphragm, it can be cured by emesis.
On the fifth day, the Foot-Shaoyin channel is affected. The Shaoyin channel belongs to the Kidney; its vessel passes through the Kidney, connects to the Lung, and attaches to the tongue. Thus, on the fifth day of illness, there is dryness of the mouth and tongue, thirst, and a desire to drink water. Since the disease is located in the intestines, it can be cured by purgation.
On the sixth day, the Foot-Jueyin channel is affected. The Jueyin channel belongs to the Liver; its vessel courses along the Yin collaterals to connect with the Liver. Thus, on the sixth day of illness, there is vexation, abdominal fullness, and retraction of the genitals. At this point, both Yin and Yang channels are affected, and toxic heat resides in the Stomach; it can be cured by purgation.
On the seventh day, the Taiyang disease begins to recede, and the headache slightly improves. According to the laws of *Shanghan*, the condition should slightly improve on the seventh day because the transmission of disease through the Yin and Yang channels has reached its conclusion. If, however, the condition worsens after the seventh day, it indicates a "Re-channel Disease" (*Zai Jing Bing*), where the meridians receive the pathogen again.
On the eighth day, the Yangming disease begins to recede, and body heat slightly improves. If the disease persists beyond eight days, it may be due to the various Yin and Yang meridians receiving the pathogen again, or because toxic heat remains incomplete after previous treatments with sweating, emesis, or purgation, hence the symptoms persist.
On the ninth day, the Shaoyang disease begins to recede, and deafness slightly improves, allowing for faint hearing. If the disease persists beyond nine days without resolution, it may be because the initial channel affected could not transmit further, or because having completed transmission through the three Yang channels, it failed to transmit to the Yin, causing stagnation for several days. Consequently, the number of days increases, and the clinical manifestations change.
On the tenth day, the Taiyin disease begins to recede; the abdomen and stomach return to normal, and the patient desires food and drink.
On the eleventh day, the Shaoyin disease begins to recede; thirst ceases, vexation and fullness disappear, and dryness of the tongue resolves.
On the twelfth day, the Jueyin disease begins to recede; the scrotum relaxes slightly, the abdomen becomes soft, toxic heat is eliminated, and the illness is nearing completion.