古者于隔蔽之义，字止作障。《说文》云∶障，隔也。是也。其作 、作鄣者，系通借
字。
由是山之隔蔽者，即易 以山而作嶂。其因山之隔蔽，致少风多湿，蒸而为气，足致民病者
，又易山以 而作瘴。观于字孳之义，而瘴之属湿可知已。瘴取隔义，则与地气发，天不应
之雾相似；而与天气发，地不应之雾为对。但患雾气者，《千金》自有症治，与治瘴之度障
散不同，足征近世混瘴于雾之非。《病源》通瘴于疫。余见东洋足本，于“青草黄芒瘴候”
，
较中国本多四百余字，所列瘴病，证治独详。第其称岭南之瘴，犹如岭北伤寒，似戾乎他论
，当是指其盛行之势相例耳！故其病不隶于伤寒诸候，而隶于疠疫，要之湿疫乃疫中之一端
，未可以概疫也。《外台》又呼瘴为疟，要之湿疟亦疟中之一端，未可以概疟也。《圣济总
录》论瘴与巢、王异，而延医加详，亦足补前人所未备。大抵瘴之发也，自有挟寒、挟热二
者。寒者白芷、桂枝、防风、槟榔等，已在度障散方中；热者犀、羚，见《本经》及《纲目
》集简方。江南山多之地，其瘴虽不比岭南之甚，然涂泥卑湿，水气适为瘴助，往往于温及
暑病发时，错出其间，故尤于犀、羚宜也。三吴老医，善使犀、羚，盖自此始，相治既久，
遂有混施之而失当者。
古人对于“隔蔽”这一含义，字形只写作“障”。《说文解字》说：“障，就是阻隔的意思。”这是正确的。那些写作“ ”（注：原文此处可能有缺字或异体，指代瘴的异体）或写作“鄣”的，属于通假字。
因此，山的阻隔遮蔽，就更换“阝”旁为“山”旁，写作“嶂”。因为山的阻隔遮蔽，导致少风多湿，湿气蒸腾成为气，足以导致百姓生病，又更换“山”旁为“疒”旁，写作“瘴”。观察汉字孳生衍化的意义，就可以知道瘴属于湿邪了。瘴取“阻隔”之意，那么它与地气上升、天气不应的雾相似；而与天气下降、地气不应的雾相对立。但是患雾气病症的人，《千金方》自有其症治方法，与治疗瘴气的度障散不同，这足以证明近代将瘴混同于雾是错误的。《诸病源候论》将瘴通用于疫气。我见过日本保存的足本，在“青草黄芒瘴候”一节中，比中国版本多出四百多字，所列出的瘴病，证候和治疗特别详细。只是它称岭南的瘴，犹如岭北的伤寒，似乎与其他论述相违背，这应当是指其盛行的态势可以类比罢了！所以这种病不属于伤寒诸候，而归属于疠疫，总之湿疫是疫气中的一种类型，不可以用湿疫来概括所有的疫气。《外台秘要》又将瘴称为疟疾，总之湿疟也是疟疾中的一种类型，不可以用湿疟来概括所有的疟疾。《圣济总录》论述瘴气与巢元方、王冰的观点不同，而延医更加详细，也足以补充前人所未完备之处。大抵瘴气的发作，自然有挟寒和挟热两种情况。挟寒的，如白芷、桂枝、防风、槟榔等药，已经在度障散的方剂中；挟热的，如犀角、羚羊角，见于《神农本草经》及《本草纲目》的集简方中。江南山多的地方，那里的瘴气虽然不比岭南严重，然而泥土低洼潮湿，水气恰好助长了瘴气，往往在温病及暑病发作时，交错出现在其间，所以对犀角、羚羊角的运用尤为适宜。三吴地区的老年医生，善于使用犀角、羚羊角，大概就是从这时开始的，相互治疗久了，于是就有混合施用而不恰当的情况出现。
In ancient times, for the meaning of "obstruction and concealment," the character was written only as *Zhang* (障). The *Shuowen Jiezi* states: "Zhang means to block or separate." This is correct. Those written as [missing character] or as *Zhang* (鄣) are phonetic loan characters.
Therefore, the obstruction caused by mountains, changing the radical from 'ear' (阝) to 'mountain' (山), becomes *Zhang* (嶂). Because the mountain's obstruction leads to little wind and much dampness, which steams into qi, sufficient to cause illness among the people, changing the radical from 'mountain' (山) to 'disease' (疒) results in *Zhang* (瘴). Observing the semantic derivation of these characters, it can be known that *Zhang* belongs to dampness. Taking the meaning of "obstruction," *Zhang* is similar to fog where earthy qi rises but heavenly qi does not respond; and it is opposite to fog where heavenly qi descends but earthly qi does not respond. However, for those suffering from fog-related illnesses, the *Qianjin Fang* has its own specific symptom treatments, which differ from the *Duzhang San* used to treat *Zhang*. This suffices to prove that the modern practice of conflating *Zhang* with fog is incorrect. The *Bingyuan* (Source of Diseases) generally conflates *Zhang* with epidemic pathogens. I have seen the complete Japanese edition, which contains over four hundred more characters than the Chinese editions in the section on "Green Grass and Yellow Tassel *Zhang* Syndrome," listing the symptoms and treatments of *Zhang* diseases in particular detail. It merely calls the *Zhang* of Lingnan analogous to the Cold Damage (*Shanghan*) of north of the ridge, which seems contrary to other discussions; this likely refers to the analogy of their prevalent momentum! Thus, this disease does not fall under the categories of Cold Damage syndromes, but is classified under pestilential epidemics (*Li Yi*). In essence, damp epidemic (*Shi Yi*) is just one aspect of epidemics and cannot be used to generalize all epidemics. The *Waitai Miyao* also refers to *Zhang* as malaria (*Nue*), but essentially, damp malaria (*Shi Nue*) is only one type of malaria and cannot be used to generalize all malaria. The *Shengji Zonglu* discusses *Zhang* differently from Chao Yuanfang and Wang Bing, providing more detailed medical consultations, which sufficiently supplements what predecessors left incomplete. Generally, the onset of *Zhang* naturally involves two types: those accompanied by cold and those accompanied by heat. For those accompanied by cold, herbs such as *Bai Zhi* (Angelicae Dahuricae Radix), *Gui Zhi* (Cinnamomi Ramulus), *Fang Feng* (Saposhnikoviae Radix), and *Bing Lang* (Arecae Semen) are already included in the formula *Duzhang San*; for those accompanied by heat, *Xi Jiao* (Rhinocerotis Cornu) and *Ling Yang Jiao* (Capricornis Subpulverizatum) are found in the *Shennong Bencao Jing* and the simplified formulas collected in the *Bencao Gangmu*. In regions south of the Yangtze with many mountains, although the *Zhang* is not as severe as in Lingnan, the low-lying and damp mud allows water qi to assist the *Zhang*, often intermingling with the onset of warm diseases and summerheat diseases. Therefore, the use of *Xi Jiao* and *Ling Yang Jiao* is particularly appropriate. Elderly physicians in the Sanwu region were skilled in using *Xi Jiao* and *Ling Yang Jiao*, starting from this period; after long-term mutual treatment, there arose cases of indiscriminate mixing and inappropriate application.