故曰:天地者，万物之上下也;阴阳者，血气之男女也;左右者，阴阳之道路也;水火者，阴阳之征兆也;阴阳者，万物之能始也。故曰:阴在内。阳之守也;阳在外，阴之使也。

“All things situate between the heaven and earth, and they are relying on the energies of heaven and earth for existence. The heaven up above is Yang and the earth down below is Yin, so the heaven and earth are the ups and downs of all things. All things are born in accordance with the change of Yin and Yang of heaven and earth. For human being, those who draw support from Yang energy abundantly are men and are of vital energy, those who draw support from Yin energy abundantly are women and are of blood, so the Yin and Yang are the man and woman of energy and blood. Within the three dimensions of heaven and earth, east and south being the left, which is Yang; west and north being the right which is Yin. Yang associates with ascent and Yin associates with descent, thus, left and right are the routs for ascent and descent of Yin and Yang. The variations of Yin and Yang are invisible, but they can be observed through the change of water (corresponds to Yin) and fire (corresponds to Yang), so water and fire are the symptoms of Yin and Yang.  Yin grows while

Yang is in vigour, and Yin becomes deficient while Yang is weakened. All things are adhering to this law in the course of life from birth to death, so Yin and Yang are the initiators of all things. In a human body, Yin resides inside and Yang guarding outside. It is only when Yang guarding outside can Yin defend inside without dispersing; and it is only due to the Yin

defending inside, can Yang operates outside.  This is the case of mutual action of Yin and Yang."

帝日:法阴阳奈何?岐伯曰:阳胜则身热，媵理闭，喘粗为之俯仰，汗不出而热，齿乾以烦冤，腹满死，能冬不能夏。阴胜则身寒，汗出，身常清，数栗(《阴证略例:阴毒三阴混说》“栗”引作“躁”而寒，寒则厥，厥则腹满死，能夏不能冬。此阴阳更胜之变，病之形能也。

Yellow Emperor asked:“How can a man regulate the Yin and Yang of his own according to the operations of Yin and Yang of heaven and earth?" Qibo answered: “Overabundance of Yang should bring about the heat of the body and the openning of the striae of skin to cause sweating. but why it is when the body is hot, that the striae of skin is closed and no sweat appears? It is because the body fluid has become dry due to the scorching by the overabudance of Yang, and the sweat lost its source so as to have no perspiration occur. The dry up of body fluid is also evidenced by the dryness of the front teeth. When the Yang energy is partial over-abundant,it will make the patient gasp rapidly with continuous bending and lifting of head; when the heat-evil stagnated inside of the body, it will make the patient irritable and depressed; the excessive heat may also cause the fullness of the abdomen of the patient. These are the fatal disease due to partial overabundance of Yang or even of pure Yang without Yin. If this kind of disease being encountered in the cold winter, the patient can still barely survive. but if it occurs in summer, the patient will surely die.

“When the Yin energy of the patient is partial overabundant, his Yang energy must be deficient, and his Wei-energy will be weakened, so his striae of skin becomes loose, his body perspires and often feels restless or even falls into coma. The patient may also feel the fullness of abdomen due to the stagnation of cold-evil. These are the fatal diseases of partial

overabundance of Yin energy while the Yang energy being cut off. In this case, the patient can still barely survive when the disease occurs in winter, but will certainly die when the disease occurs in summer. The above statements show the symptom of the pathological change of Yin and Yang imbalance. "

帝曰:调此二者奈何?岐伯曰:能知七损八益，则二者可调;不知用此，则早衰之节[《甲乙》无“之节”二字)也。年四十，而阴气自半也，起居衰矣;年五十，体重，耳目不聪明矣;年六十，阴痿，气大衰，九窍不利，下虚上实，涕泣俱出矣。故曰:知之则强，不知则老，故同出而名异耳。智者察同，愚者察异。愚者不足，智者有余，有余则耳目聪明，身体轻强，老者复壮，壮者益治。是以圣人为无为之事，乐恬儋之能，从欲快志于虚无之守，故寿命无穷，与天地终，此圣人之治身也。

Yellow asked: "But how to regulate properly the energies of Yin and Yang?” Qibo answered: “If one can regulate the Yin and Yang according to the physiological rule of seven disadvantages and eight advantages of men and women, one will promise longevity, if one can not do it properly, one would become early ageing.

“The Tiangui (substance origins from the kidney essence necessary for regulation of growth and reproduction) of man exhausts at the age of 64 (8 x 8). When he is 40 (5 x 8), only half of his Yin energy is left over, and his actions in daily life become weak. When he is 50, his blood and energy decline and his body becomes clumsy. As the essence and blood are

insufficient to nourish oneself, his eyes and ears are no more accute. At the age of 60 which is approaching 64 (8 x 8), his Tiangui becomes exhausted, his kidney being declined and he becomes impotent. The kidney energy is the primordial true energy, when it is declined, the solid and hollow organs energies will all be weakened and can no more nourish the nine orifices and they will be no more facile. Since the Yang energy below is feeble and the Yin energy above is overabundant, it causes the tears to come out. This is the case when one fails to regulate the Yin and Yang properly and causes early ageing.

“Therefore, when one knows how to regulate the Yin and Yang properly will make his body strong, and his body will become decrepit and senile when not knowing how to regulate it. All the people live by drawing support from the energies of heaven and earth, but some of them live a long life and some die early due to their different achievments of health protecting. This is because a wise man can preserve his health before senility while a stupid man can only discover the fact after his senility has occurred. Thus, a wise man can remain strong constantly and have enough essence and blood to spare, while a stupid man is always short of essence and blood. When one's essence and blood are ample, his body will be healthy and strong, his eyes and ears will be able to see and hear clearly, for an aged man, he can still have a strong body, for a young man, he will be even stronger.

"So the sages do nothing that is unprofitable to health preserving, find pleasure in the mode of indifferent to fame and gain and free from distracting thoughts, follow what the heart desire leisurely and take delight in the state of having no desire, so that their life may be endless and ever-lasting as the heaven and earth. This is the way of the sages to preserve health.

天不足西北，故西(《太素》“西”下无“北”字]北方阴也，而人右耳目不如左明也。地不满东南，故东(《太素》“东”下无“南”字)南方阳也，而人左手足不如右强也。帝日:何以然?岐伯日:东方阳也，阳者其精并于上，并于上则上明(《类说》“明”引作“盛”而

下虚，故使耳目聪明而手足不便也。西方阴也，阴者其精并于下，并于下则下盛而上虚，故其耳目不聪明而手足便也。故俱感于邪，其在上则右甚，在下则左甚，此天地阴阳所不能全也，故邪居之。

“The sky is lacking in north-west, and west corresponds to Yin, so the right eyes and ears of a man are not so acute as the left ones. The earth is not full in south-east, and east is Yang, so the left hand and foot of a man are not so strong as the right ones. This is to show the human body is matching the heaven and earth, and they are not perfect.”

The Yellow Emperor asked:“Why is it so?" Qibo answered: “The east corresponds to Yang, when both Yang and the its essence staying above, the lower part of the body must be in debility, thus making the ears and eyes acute but the hands and feet not so facile.  The west corresponds to Yin, when both Yin and its essence staying below, the upper part must

be in debility making the ears and eyes not so acute but the hands and feet nimble. It is precisely because of the phenomena of Yin, Yang and essence being partial overabundant in the upper part or the lower part of the body, so as to cause the body to become overabundant above and in debility below or the vice versa. When evil is contracted, different cases may occur, such as in the upper part diseases of ‘Yin and its essence both staying below and cause debility of the upper part’, the disease in the right side is more serious than that of the left side (right corresponds to Yin), in the lower part diseases of ‘Yang and its essence both staying above to cause debility of the lower part’, the disease in the left side is more serious that that of the right side (left corresponds to Yang). This is because of the human, heaven and earth are not perfect in every way, and the evil energy takes advantage of the debility to reside.