仲景以太阳冬月司令之伤寒,酌以麻黄汤治寒邪伤营,无汗发热之表症,以桂枝汤治风邪伤
卫,有汗发热之表症。然此按北方方宜,分经络,立规矩,为后世指南者也,施治三时,施
之江浙则不合。赖陶氏发明仲景麻黄、桂枝二汤,此治冬月正伤寒之方,非治春夏秋三时之
热病,易以羌活冲和汤,实为至当。但失注麻桂二汤,乃是北方治法,江浙东南,即冬月亦
不宜用;即或内无积热,偶冒暴寒,未经郁热者,暂亦用之,然不可为常法。如此分别,后
人判然,不以仲景麻黄、桂枝借口。然羌活冲和汤,解表清里和解三阳之方,但可治三时表
里兼见之症;若纯是表邪外束,则生地、黄芩,原非发散寒邪之药。今余以羌活败毒散发散
三时太阳纯表之症,以羌活冲和汤和解太阳表里俱见之症,次以葛根汤以治阳明纯表之症,
以干葛石膏汤为阳明和解之方,再以柴葛解肌汤治少阳阳明表里居多之症,又以小柴胡汤为
少阳和解之方,如此虽变仲景之方,以合江浙方宜,实遵仲景之旨也。
仲景清里方法,以里有结热,即当清里。故立五苓散以清太阳里热,立白虎汤以清阳明里
热,立黄芩汤以清少阳里热。若热结大肠、下症悉具者,有承气汤以下之。又有三黄汤、凉
膈散、导赤各半汤、黄连泻心汤,通治三焦里热之症。盖因里热煎熬,津液有立尽之势,故
清之以存津液。然则清里之法,不特南方应如此,夏秋应如此,即冬月,即北方亦如此者。
陶氏云∶发表之药,三时不得与冬月正伤寒同治,为清里可与冬月正伤寒同治。陶氏分别时
令,今余更分南北方宜。夫北方寒凉之地,又加之冬月伤寒,时令方宜,皆宜辛温散表,故
立桂枝麻黄主治;若南离已午之地,发表之药不与北方同治,惟清里之药南北可同者。
张仲景将冬季当令的伤寒归属于太阳病,斟酌使用麻黄汤来治疗寒邪损伤营分、表现为无汗发热的表证;使用桂枝汤来治疗风邪损伤卫分、表现为有汗发热的表证。然而,这是按照北方地区的适宜治法,区分经络,确立规范,作为后世的指南。如果在春、夏、秋三个季节施用,或者在江浙地区施用,就不合适了。幸亏陶华(陶节庵)阐明了张仲景的麻黄汤和桂枝汤这两个方剂,是治疗冬季正伤寒的方子,而不是治疗春夏秋三季的热病。因此改用羌活冲和汤,这确实是极为恰当的做法。但是,如果不注明麻黄汤和桂枝汤乃是北方的治法,那么在江浙东南地区,即使是冬季也不宜使用;即便体内没有积热,偶然冒犯暴寒,且尚未出现郁热的情况,暂时也可以使用,但这不能作为常规法则。如此分别清楚,后人就能明辨,不再借口引用张仲景的麻黄汤和桂枝汤。然而,羌活冲和汤是解表清里、和解三阳的方剂,只能治疗三季表里症状同时出现的病症;如果是纯粹的表邪外束,那么生地黄、黄芩原本就不是发散寒邪的药物。如今我以羌活败毒散来发散三季太阳病纯表证的病症,以羌活冲和汤来和解太阳病表里俱见的病症,其次用葛根汤来治疗阳明病纯表证的病症,以干葛石膏汤作为阳明病的和解方剂,再用柴葛解肌汤治疗少阳病与阳明病表里症状居多的病症,又以小柴胡汤作为少阳病的和解方剂。像这样虽然改变了张仲景的方剂,以符合江浙地区的适宜治法,但实际上是遵循张仲景的宗旨。
张仲景清里的方法,认为如果里有结聚之热,就应当清里。因此设立五苓散来清除太阳经的里热,设立白虎汤来清除阳明经的里热,设立黄芩汤来清除少阳经的里热。如果热邪结聚在大肠,下法的症状全部具备,则有承气汤来攻下。又有三黄汤、凉膈散、导赤各半汤、黄连泻心汤,通治三焦里热的病症。这是因为里热煎熬,津液有立刻耗尽的趋势,所以通过清热来保存津液。既然这样,清里的方法,不仅南方应该这样做,夏秋季节应该这样做,即使是冬季,即使是北方也应该这样做。陶华说:“发表的药物,在春、夏、秋三季不能与冬季正伤寒同治,但清里的药物可以与冬季正伤寒同治。”陶华分别了时令的差异,如今我更区分南北方地域的适宜治法。因为北方是寒冷之地,又加上冬季伤寒,时令和地域的适宜治法,都应当用辛温药物发散表邪,所以设立桂枝汤和麻黄汤主治;而南方处于离火方位(指气候较暖),发表的药物不与北方相同治疗,只有清里的药物南北方可通用。
Zhang Zhongjing classified winter-onset cold damage (Shanghan) under the Taiyang stage. He prescribed Mahuang Tang to treat exterior syndromes characterized by fever and absence of sweating caused by cold pathogenic factors damaging the Ying (Nutritive) level; and Guizhi Tang to treat exterior syndromes characterized by fever and sweating caused by wind pathogenic factors damaging the Wei (Defensive) level. However, this approach follows the therapeutic principles suitable for Northern China, differentiating meridians and establishing rules as a guide for later generations. Applying these treatments during the spring, summer, and autumn seasons, or in the Jiangzhe region, would be inappropriate. Fortunately, Tao Hua elucidated that Zhang Zhongjing's Mahuang Tang and Guizhi Tang are formulas for treating true Shanghan in winter, not for treating heat diseases in spring, summer, and autumn. It is therefore appropriate to substitute them with Qianghuo Chonghe Tang. Nevertheless, if it were not noted that Mahuang Tang and Guizhi Tang are Northern treatment methods, they should not be used even in winter in the Jiangzhe southeastern regions. Even if there is no accumulated heat internally and one accidentally encounters sudden cold without subsequent heat constraint, temporary use may occur, but this cannot become a standard method. With such clear distinctions, later practitioners can differentiate clearly and will not use Zhang Zhongjing's Mahuang Tang and Guizhi Tang as excuses. However, Qianghuo Chonghe Tang is a formula for releasing the exterior, clearing interior heat, and harmonizing the three Yang stages; it is only suitable for syndromes where exterior and interior symptoms appear simultaneously during the three non-winter seasons. If the condition is purely an exterior constraint by pathogenic factors, then Shengdi Huang (Rehmanniae Radix Preparata) and Huangqin (Scutellariae Radix) are originally not herbs for dispersing cold pathogens. Now, I use Qianghuo Baidu San to disperse pure exterior syndromes of the Taiyang stage during the three non-winter seasons, and Qianghuo Chonghe Tang to harmonize Taiyang syndromes presenting both exterior and interior symptoms. Secondly, I use Gegen Tang to treat pure exterior syndromes of the Yangming stage, and Gan Ge Shigao Tang as a harmonizing formula for the Yangming stage. Furthermore, I use Chaige Jieji Tang to treat syndromes of the Shaoyang and Yangming stages where exterior and interior symptoms predominate, and Xiaochaihu Tang as a harmonizing formula for the Shaoyang stage. Although this modifies Zhang Zhongjing's formulas to suit the regional preferences of Jiangzhe, it actually adheres to the intent of Zhang Zhongjing.
Regarding Zhang Zhongjing's methods for clearing the interior: if there is constrained heat within, the interior must be cleared. Thus, Wuling San was established to clear interior heat of the Taiyang stage; Baihu Tang to clear interior heat of the Yangming stage; and Huangqin Tang to clear interior heat of the Shaoyang stage. If heat constrains the Large Intestine and all symptoms requiring purgation are present, Chengqi Tang is used for purgation. Additionally, Sanhuang Tang, Liangge San, Daochi Banjie Tang, and Huanglian Xiexin Tang are used to treat interior heat syndromes of the Triple Burner generally. This is because interior heat cauterizes fluids, creating a situation where body fluids are on the verge of complete exhaustion; thus, clearing heat preserves body fluids. Consequently, the method of clearing the interior applies not only in Southern China and during summer and autumn, but also in winter and in Northern China. Tao Hua stated: "Exterior-releasing herbs should not be treated the same in the three non-winter seasons as in true winter Shanghan, but interior-clearing herbs can be treated the same as in true winter Shanghan." Tao Hua differentiated based on seasons; now I further differentiate based on Northern and Southern regional suitability. Because the North is a cold region, compounded by winter Shanghan, both seasonal and regional suitability dictate the use of acrid-warm herbs to release the exterior; hence, Guizhi Tang and Mahuang Tang are established for treatment. In contrast, the South corresponds to the Li Fire direction (implying warmer climate), so exterior-releasing herbs are not treated the same as in the North; only interior-clearing herbs are applicable uniformly across North and South.