3.医明阴阳五行理, 始晓天时民病情. 五运五行五气化, 六气天地
阴阳生. 火分君相气热暑, 为合人之脏腑经. 天干起运地支气, 天五
地六节制成.
【注】学医业者, 必要明天地阴阳, 五行之理, 始晓天时之和不和,
民之生病之情由也. 人皆知五运化自五行, 五质, 五气也, 而不知六
气化自天地阴阳、六质、六气也. 六质者, 即经曰木, 火, 土, 金,
水,火, 地之阴阳也. 生, 长, 化, 收, 藏下应之也. 六气者, 即经
曰风, 暑, 湿, 燥, 寒, 火, 天之阴阳也, 三阴三阳上奉之也. 是以
在地之火分为君火, 相火; 在天之气分为热气, 暑气, 为合人之五脏
六腑, 包络十二经也. 天干阴阳合而为五, 故主五运. 甲化阳土, 合
人之胃. 己化阴土, 合人之脾. 乙化阴金, 合人之肺. 庚化阳金, 合
人大肠. 丙化阳水, 合人膀胱. 辛化阴水, 合人之肾. 丁化阴木, 合
人之肝. 壬化阳木, 合人之胆. 戊化阳火, 合人小肠. 癸化阴火, 合
人之心. 相火属阳者, 合人三焦. 相火属阴者, 合人包络. 此天干合
人之五脏六腑十二经也. 地支阴阳合而为六, 故主六气. 子午主少阴
君火, 合人之心与小肠也. 丑未太阴湿土, 合人之脾与胃也. 寅申主
少阳相火, 合人之三焦包络也. 卯酉主阳明燥金, 合人之肺与大肠也
.辰戌主太阳寒水, 合人之膀胱与肾也. 巳亥主厥阴风木, 合人之肝
与胆也. 此地支之合人五脏六腑十二经也. 天数五, 而五阴, 五阳,
故为十干. 地数六, 而六阴、六阳, 故为十二支. 天干之五, 必得地
支之六以为节, 地支之六, 必得天干之五以为制, 而后六甲成, 岁气
备.故一岁中运, 以七十二日五位分主之, 六气以六十日六步分主之
也( 图五, 六 ).
3. 医学必须阐明阴阳五行的道理，才能知晓天时气候与民众病情的关系。五运、五行、五气相互化生，六气源于天地阴阳的变化。火分为君火和相火，热气与暑气相应，这与人的脏腑经络相合。天干决定五运，地支决定六气，天的数五与地的数六节制而成规律。
【注】从事医学行业的人，必须明白天地阴阳、五行的道理，才能知晓天时气候是否调和，以及民众生病的原因。人们都知道五运由五行化生，对应五种物质（五质）和五种气化（五气），却不知道六气由天地阴阳化生，对应六种物质（六质）和六种气化（六气）。所谓的“六质”，即《内经》所说的木、火、土、金、水，加上火，这是地之阴阳。它们分别对应生长、化育、收敛、闭藏的过程。所谓的“六气”，即《内经》所说的风、暑、湿、燥、寒、火，这是天之阴阳，由三阴三阳上承奉应。因此，在地之火分为君火和相火；在天之气分为热气和暑气，这些与人体的五脏、六腑、心包络及十二经脉相合。天干的阴阳结合成为五组，所以主管五运。甲化为阳土，对应人的胃；己化为阴土，对应人的脾；乙化为阴金，对应人的肺；庚化为阳金，对应人的大肠；丙化为阳水，对应人的膀胱；辛化为阴水，对应人的肾；丁化为阴木，对应人的肝；壬化为阳木，对应人的胆；戊化为阳火，对应人的小肠；癸化为阴火，对应人的心。属于阳的相火，对应人的三焦；属于阴的相火，对应人的心包络。这就是天干与人的五脏六腑十二经的对应关系。地支的阴阳结合成为六组，所以主管六气。子午年主少阴君火，对应人的心与小肠；丑未年主太阴湿土，对应人的脾与胃；寅申年主少阳相火，对应人的三焦与心包络；卯酉年主阳明燥金，对应人的肺与大肠；辰戌年主太阳寒水，对应人的膀胱与肾；巳亥年主厥阴风木，对应人的肝与胆。这就是地支与人的五脏六腑十二经的对应关系。天的数是五，有五阴五阳，所以有十个天干。地的数是六，有六阴六阳，所以有十二个地支。天干的五，必须得到地支的六来节制；地支的六，必须得到天干的五来制约，然后六十甲子才形成，岁气才完备。所以一年中的五运，以七十二日五位分主之；六气以六十日六步分主之（见图五、图六）。
3. Medicine must elucidate the principles of Yin-Yang and Five Elements (Wu Xing) to understand the relationship between celestial climate and human pathology. The Five Movements (Wu Yun), Five Elements, and Five Qi transform into one another; the Six Qi (Liu Qi) arise from the changes of Heaven and Earth's Yin-Yang. Fire is divided into Ministerial Fire (Xiang Huo) and Sovereign Fire (Jun Huo); Heat Qi (Re Qi) and Summer-heat Qi (Shu Qi) correspond thereto, aligning with the human Zang-Fu organs and meridians. Heavenly Stems determine the Five Movements, Earthly Branches determine the Six Qi; the number of Heaven (5) and the number of Earth (6) form a regulated pattern.
[Note] Practitioners of medicine must comprehend the principles of Heaven and Earth's Yin-Yang and the Five Elements to discern whether the celestial climate is harmonious and to understand the causes of disease among the people. Everyone knows that the Five Movements derive from the Five Elements, corresponding to five substances (Wu Zhi) and five qi transformations. However, they do not realize that the Six Qi derive from the Yin-Yang of Heaven and Earth, corresponding to six substances (Liu Zhi) and six qi transformations. The "Six Substances" refer to Wood, Fire, Earth, Metal, Water, and Fire as mentioned in the Classics; this constitutes the Yin-Yang of the Earth. They correspond to the processes of Birth (Sheng), Growth (Zhang), Transformation/Transformation (Hua), Harvest/Convergence (Shou), and Storage (Cang). The "Six Qi" refer to Wind, Summer-heat, Dampness, Dryness, Cold, and Fire as mentioned in the Classics; this constitutes the Yin-Yang of Heaven, upheld by the Three Yin and Three Yang. Therefore, Fire on Earth is divided into Sovereign Fire and Ministerial Fire; Qi in Heaven is divided into Heat Qi and Summer-heat Qi. These correspond to the human Five Zang organs, Six Fu organs, Pericardium (Bao Luo), and Twelve Meridians. The Yin-Yang of Heavenly Stems combine to form five pairs, thus governing the Five Movements. Jia transforms into Yang Earth, corresponding to the Human Stomach. Ji transforms into Yin Earth, corresponding to the Spleen. Yi transforms into Yin Metal, corresponding to the Lung. Geng transforms into Yang Metal, corresponding to the Large Intestine. Bing transforms into Yang Water, corresponding to the Bladder. Xin transforms into Yin Water, corresponding to the Kidney. Ding transforms into Yin Wood, corresponding to the Liver. Ren transforms into Yang Wood, corresponding to the Gallbladder. Wu transforms into Yang Fire, corresponding to the Small Intestine. Gui transforms into Yin Fire, corresponding to the Heart. Ministerial Fire belonging to Yang corresponds to the Sanjiao (Triple Burner). Ministerial Fire belonging to Yin corresponds to the Pericardium. This describes the correspondence between Heavenly Stems and the human Five Zang, Six Fu, and Twelve Meridians. The Yin-Yang of Earthly Branches combine to form six pairs, thus governing the Six Qi. Zi and Wu govern Shaoyin Sovereign Fire, corresponding to the Heart and Small Intestine. Chou and Wei govern Taiyin Damp-Earth, corresponding to the Spleen and Stomach. Yin and Shen govern Shaoyang Ministerial Fire, corresponding to the Sanjiao and Pericardium. Mao and You govern Yangming Dry-Metal, corresponding to the Lung and Large Intestine. Chen and Xu govern Taiyang Cold-Water, corresponding to the Bladder and Kidney. Si and Hai govern Jueyin Wind-Wood, corresponding to the Liver and Gallbladder. This describes the correspondence between Earthly Branches and the human Five Zang, Six Fu, and Twelve Meridians. The number of Heaven is five, comprising five Yin and five Yang, hence there are ten Heavenly Stems. The number of Earth is six, comprising six Yin and six Yang, hence there are twelve Earthly Branches. The five of Heavenly Stems must obtain the six of Earthly Branches for regulation; the six of Earthly Branches must obtain the five of Heavenly Stems for constraint. Only then are the sixty Jiazi cycles formed, and the annual Qi complete. Thus, within one year, the Five Movements are governed by five positions over seventy-two days each, and the Six Qi are governed by six steps over sixty days each (see Figures 5 and 6).