时生于庭，随月凋荣；朔后一日荚生，望后一日荚落，历得其分度则 荚生。）天有昼夜，人有卧起。（昼为
阳，人应阳而动；夜为阴，人应阴而静。）天有列星，人有牙齿。（齿牙疏朗，故象似列星。女子三七，男子三
八，则真牙生而长极，是以后生之大者为牙也。女子七岁，男子八岁齿更，是以前生之小者为齿也。故男子
八月生齿，八岁而龀；女子七月生齿，七岁而龀。龀，毁齿也。龀，抄近切。）地有小山，人有小节。
（小节者，小骨指节之类。）地有山石，人有高骨。（高骨，颧肩膝踝之类。）地有林木，人有募筋。（募者，
筋脉聚蓄之处。募，音暮。）地有聚邑，人有 肉。（ 肉者，脂肉之聚处也。）岁有十二月，人有十
二节。（四肢各三节，是为十二节。）地有四时不生草，人有无子。
（地有不毛之地，人有不育之人。）此人与天地相应者也。
妇人无须者，冲脉、任脉皆起于胞中，上循背里，为经络之海，（凡男妇之有须、无须者，皆由于冲、
任二脉之血有盛衰也。冲、任为经络之海，其起脉之处则在胞中，而上行于背里。所谓胞者，子
宫是也，此男女藏精之所，皆得称为子宫，惟女子于此受孕，因名曰胞。然冲、任、督脉皆起于此，所谓一
原而三歧也。）其浮而外者，循腹右上行，会于咽喉，别而络唇口。血气盛则充肤热肉，血独盛
则淡渗，皮肤生毫毛。（冲、任，阴脉也，故循腹右上行。然左乳之下则有胃之大络，此正左阳右阴相配之妙
也。）今妇人之生，有余于气，不足于血，以其数脱血也。冲任之脉，不荣口唇，故须不生焉。（数脱血，
谓血不留而月事以时下也。冲任为血之海，须为血之余，血不足则冲任之脉不荣于口而须不生矣。数，音朔。）
士人有伤于阴，阴气绝而不起，其须不去。（阴不用者，阳痿不举也。此言士人之阴伤而绝者，其须不去。）
宦者，去其宗筋，伤其冲脉，血泻不复，皮肤内结，唇口不荣，故须不生。（士人者，阴气虽伤而宗
筋未坏；彼宦官者，去其宗筋而伤其冲脉矣。血一泻而不能复，皮肤内结而经道不行，故冲脉不荣于口而须
不生也。）有天宦者，未尝被伤，不脱于血，然其须不生，（谓身为男子而终身无须，若天生之宦然，
故曰“天宦”。）此天之所不足也；其任冲不盛，宗筋不成，有气无血，唇口不荣，故须不生。（天之所不
足，言先天所禀有任冲之不足者，故亦不生须也。）是故视其颜色∶黄赤者多热气，青白者少
热气，黑色者多血少气；（黄赤者为阳，青白黑者为阴也。）美眉者太阳多血，通髯极须者少阳多血，
美须者阳明多血，此其时然也。（在颊曰髯，在口下及两颐者曰须，在口上曰髭。凡此所言者，即
其经行之地。）夫人之常数，太阳常多血少气，少阳常多气少血，阳明常多血多气，厥阴常多气少血，少阴
常多血少气，太阴常多血少气，此天之常数也。（十二经之血气多少，各有不同。
气血多少四字极易混乱，传录之误也。当以所论血气形志者为是。）
Xue Xue (author) in the courtyard, (observing that plants) wither or flourish following the waxing and waning of the moon; on the first day after the new moon, pods begin to grow, and on the first day after the full moon, pods fall off. (The growth cycle of plants) corresponds to the lunar phases according to calendrical measurements. The heaven has day and night, and humans have sleeping and waking. (Day belongs to Yang, and humans follow Yang to be active; night belongs to Yin, and humans follow Yin to be quiet.) The heaven has rows of stars, and humans have teeth. (Teeth are neat and orderly, thus resembling the arrangement of stars. When women reach twenty-one sui [years old] and men reach twenty-four sui, wisdom teeth erupt and physical development reaches its peak; hence, the larger teeth that grow later are called "ya" [wisdom teeth]. When women are seven sui and men are eight sui, deciduous teeth are replaced; hence, the smaller teeth that grew earlier are called "chi" [deciduous teeth]. Therefore, men's deciduous teeth emerge at eight months of age and are shed at eight sui; women's deciduous teeth emerge at seven months of age and are shed at seven sui. "Chen" refers to the shedding of deciduous teeth. "Chen" is pronounced as 'chao jin'.) The earth has small hills, and humans have small joints. ("Small joints" refer to the small bone segments of fingers and toes.) The earth has mountains and rocks, and humans have prominent bones. ("Prominent bones" refer to high points such as the zygomatic bone, acromion, knee, and ankle.) The earth has forests, and humans have areas where sinews gather. ("Mu" refers to the places where meridians and collaterals accumulate Qi and Blood. "Mu" is pronounced as 'mu'.) The earth has gathered cities, and humans have accumulations of fatty muscle. ("Fatty muscle" refers to the sites where fat and muscle tissue aggregate.) There are twelve months in a year, and humans have twelve major joints. (Each of the four limbs has three major joints, totaling twelve joints.) There are barren lands where grass does not grow in the four seasons, and there are people who cannot reproduce. (Just as there is barren land, there are infertile people.) This illustrates how humans correspond to Heaven and Earth.
Women do not have beards because the Chong Mai (Penetrating Vessel) and Ren Mai (Conception Vessel) both originate from the Bao Zhong (Uterus/Cavity), ascend along the interior of the back, and serve as the Sea of Meridians and Collaterals. (Whether men or women have beards depends entirely on the abundance or deficiency of Qi and Blood in the Chong and Ren vessels. As the Sea of Meridians, their origin is in the Bao Zhong, ascending to the interior of the back. The term "Bao Zhong" refers to the uterus, which is the repository of essence for both men and women and can be termed the uterus; however, only in women does conception occur here, so it is specifically named "Bao". Nevertheless, the Chong, Ren, and Du Mai (Governing Vessel) all originate here, known as "one source branching into three.") Their branches floating superficially ascend along the right side of the abdomen, converge at the throat, and branch out to connect with the lips and mouth. Abundant Qi and Blood fill the skin and warm the flesh; if Blood is particularly abundant, it permeates lightly, causing fine hairs to grow on the skin. (The Chong and Ren vessels are Yin vessels, hence they ascend along the right side of the abdomen. However, below the left breast lies the great Luo vessel of the Stomach, illustrating the subtle coordination of Left-Yang and Right-Yin.) Now, women are born with an excess of Qi but a deficiency of Blood, due to frequent blood loss (menstruation). Since the Chong and Ren vessels fail to nourish the lips and mouth, beards do not grow. ("Frequent blood loss" refers to blood not stagnating but flowing regularly as menstruation. The Chong Mai is the Sea of Blood, and hair/beard is the surplus of Blood; when Blood is deficient, the Qi of the Chong and Ren vessels fails to nourish the mouth area, so beards do not grow. "Shuo" is pronounced as 'shuo'.)
Scholars (ordinary men) who injure their Zong Jin (Genitals/Root Sinew) may experience exhaustion of Yin Qi leading to impotence, yet their beards will not fall out. (Impotence indicates the failure of Yin Qi function. This passage states that even if a scholar's Yin Qi is injured and exhausted, his beard remains.) Eunuchs, whose Zong Jin has been removed and Chong Mai injured, suffer from irreversible blood loss. Internal stagnation occurs in the skin, the lips and mouth lack nourishment, and thus beards do not grow. (For scholars, although Yin Qi is injured, the Zong Jin remains intact; for eunuchs, the Zong Jin is removed and the Chong Mai damaged. Once blood is lost, it cannot recover; internal skin stagnation blocks the meridian pathways, so the Chong Mai fails to nourish the mouth, and beards do not grow.) There exists a condition called "Tian Huan" (Heavenly Eunuch/Conital Eunuch), where individuals have never suffered trauma nor experienced blood loss, yet they do not grow beards. (This refers to males who are beardless throughout life, resembling congenital eunuchs, hence the name "Tian Huan".) This results from congenital insufficiency; their Ren and Chong vessels are not vigorous, the Zong Jin fails to develop properly, there is Qi but insufficient Blood, the lips and mouth are not nourished, and thus beards do not grow. ("Congenital insufficiency" implies a先天 (innate) deficiency in the Ren and Chong vessels, leading to the absence of beards.)
Therefore, observe their complexion: Yellowish-red complexions indicate excessive Heat; bluish-white complexions indicate little Heat; black complexions indicate abundant Blood but deficient Qi. (Yellowish-red belongs to Yang; bluish-white and black belong to Yin.) Those with beautiful eyebrows have abundant Blood in the Taiyang Mai (Greater Yang Vessel); those with dense cheek beards have abundant Blood in the Shaoyang Mai (Lesser Yang Vessel); those with beautiful chin beards have abundant Blood in the Yangming Mai (Yang Brightness Vessel). This reflects the natural timing of meridian distribution. ("Ran" refers to cheek hair; "Xu" refers to hair under the mouth and on the jawlines; "Zi" refers to mustache hair above the mouth. These descriptions correspond to the pathways of these meridians.) The constant norms of the human body are: Taiyang Mai typically has abundant Blood and deficient Qi; Shaoyang Mai typically has abundant Qi and deficient Blood; Yangming Mai typically has abundant Blood and abundant Qi; Jueyin Mai typically has abundant Qi and deficient Blood; Shaoyin Mai typically has abundant Blood and deficient Qi; Taiyin Mai typically has abundant Blood and deficient Qi. These are the innate constants. (The amounts of Qi and Blood in the twelve meridians vary. Statements regarding Qi and Blood quantities are often confused due to transcription errors. One should rely on the discussion in the *Ling Shu* chapter on "Five Tones and Five Colors" regarding the forms and spirits of Qi and Blood.)