汪石山论寒热互发者，盖气少不能营运，而滞于血分，故发热；血少不能流利，而滞于气分
，故发寒。仲景云∶阳入于阴则热，阴入于阳则寒，是也。寒则战栗鼓颔者，阴邪入于阳分
也；热则咳痰不已者，阳邪入于阴分也。此则阴阳两虚，故相交并而然也。
慎斋云∶伤寒寒热往来，系邪在半表半里；内伤寒热，系气血两虚。气虚则发热，血虚则发寒。
凡肌表发热，皆邪阳胜，正阳虚也。用黄 、附子，所以助阳。盖阳气既虚，黄 性
缓，不能到表，须得附子雄壮之气，引 直走于表，助之成功也。
《灵枢》云∶神伤于思虑，则肉脱；意伤于忧愁，则肢废；魂伤于悲哀，则筋挛；魄伤
于喜乐，则皮槁；志伤于盛怒，则腰脊难以俯仰也。
褚先生精血篇云∶男子精未通，而御女以通其精，则五体有不满之处，异日有难状之疾
。阴已痿，而思色以降其精，则精不出而内败，小便道涩而为淋；精已耗而复竭之，则
大小便道牵痛，愈疼则愈欲小便，愈便则愈疼。又云∶女人天癸既至，逾十年无男子合，则
不调；未逾十年，思男子合，亦不调。不调则旧血不出，新血误行，或溃而入骨，或变而之
肿，或虽合而难子。合男子多，则沥枯虚人；乳产众，则血枯杀人。观其精血，思过半矣。
为月水，为经络之余气。苟外无六淫所侵，内无七情所伤，脾胃之气壮，则冲任之气盛，故
月水适时而至。然有面色萎黄，四肢消瘦，发热口干，月水过期且少。乃阴血不足，非有余
瘀闭之证，宜以滋血气之剂徐培之，使经气盛，水自根据时而下。
又云∶凡放出宫人，及少年孀妇，年逾三十，两跨作痛，而肤不肿，色不变，或大小便
如淋，登厕尤痛，此血瘀渍入隧道为患，乃男女失合之证也。（若渍入肠胃，即为血臌。经
云∶腹里大，脓血在肠胃之外，小便涩而奇痛，不可作水利之。）
丹溪云∶肾主闭藏，肝主疏泄。二脏俱有相火，而其系上属于心，心为君火，为物所感
则易动。心动则相火翕然而随，虽不交合，其精暗耗矣。
汪石山论述寒热交替发作的原因，是因为气虚不能正常运行，而停滞在血分中，所以发热；血虚不能流畅运行，而停滞在气分中，所以发冷。张仲景说：阳气进入阴分则发热，阴气进入阳分则发冷，说的就是这个道理。发冷时出现战栗、咬牙的现象，是阴邪侵入阳分；发热时咳嗽痰多不止，是阳邪侵入阴分。这种情况属于阴阳两虚，所以相互交争而导致上述症状。
慎斋（胡慎柔自称）说：伤寒病中的寒热往来，是由于病邪位于半表半里之间；内伤引起的寒热，是由于气血两虚。气虚就会发热，血虚就会发冷。凡是肌表发热，都是邪气亢盛，正气（真阳）虚弱所致。使用黄芪、附子，是为了辅助阳气。因为阳气既然已经虚弱，黄芪药性缓和，不能到达体表，必须依靠附子雄壮之气，引导黄芪直达体表，从而帮助治疗成功。
《灵枢》说：神志因过度思虑而受伤，肌肉就会消瘦脱失；意念因忧愁而受伤，四肢就会废用不用；魂因悲哀而受伤，筋脉就会拘挛抽搐；魄因喜乐过度而受伤，皮肤就会干枯；意志因大怒而受伤，腰脊就难以俯仰活动。
褚先生《精血篇》说：男子精气尚未通畅时，就与女子行房以泄精，那么五脏形体就会有不完备的地方，日后会有难以形容的疾病。如果阴茎已痿软，却还想着美色来泄精，那么精液排不出而在体内败坏，小便通道涩滞而成为淋证；精气已经耗损却又再次竭尽，那么大、小便通道都会牵拉疼痛，越疼越想小便，越小便就越疼。又说：女子天癸（月经）已经来潮，过了十年没有男子交合，月经就会不调；未满十年，心里想着与男子交合，月经也会不调。月经不调则旧血不能排出，新血错误地流动，有的溃烂深入骨骼，有的变成肿胀，或者虽然交合但难以怀孕。与男子交合过多，会导致精液枯竭、身体虚弱；生育众多，会导致血液枯竭甚至死亡。观察精血的损耗，大概就能明白一半的道理了。（注：此处原文可能有缺漏或排版问题，通常指经水源于精血）。月经是由经络的余气形成的。假如外没有六淫（风、寒、暑、湿、燥、火）侵袭，内没有七情（喜、怒、忧、思、悲、恐、惊）伤害，脾胃之气强壮，那么冲任二脉之气就旺盛，所以月经能按时来潮。然而有的人面色萎黄，四肢消瘦，发热口干，月经过期且量少。这是阴血不足，不是有余瘀血闭阻的证候，应该用滋养气血的药剂慢慢培补，使经气旺盛，月经自然按时而下。
又说：凡是放出宫的宫女，以及年轻的寡妇，年龄超过三十岁，两侧胯部作痛，但皮肤不肿，颜色不变，或者大小便像淋证一样，上厕所时尤其疼痛，这是瘀血浸渍入隧道（指下焦经络或尿道等）造成的祸患，属于男女失于交合的证候。（如果瘀血浸渍入肠胃，就会形成血臌。经书说：腹部胀大，脓血在肠胃之外，小便涩滞且剧烈疼痛，不可当作水利病治疗。）
朱丹溪说：肾主闭藏，肝主疏泄。这两脏都含有相火，而其联系上属于心，心为君火，受到外界事物感应就容易动。心动则相火随之翕然而起，即使不进行性交，精气也在暗中消耗了。
Wang Shishan discussed the cause of alternating chills and fever, attributing it to Qi deficiency failing to circulate properly, leading to stagnation in the Blood aspect, thus causing fever; and Blood deficiency failing to flow smoothly, leading to stagnation in the Qi aspect, thus causing cold. Zhang Zhongjing stated: "When Yang enters Yin, there is heat; when Yin enters Yang, there is cold." This is correct. Chills with shivering and teeth grinding indicate Yin pathogenic factors entering the Yang aspect; fever with incessant coughing and expectoration indicates Yang pathogenic factors entering the Yin aspect. This situation arises from dual deficiency of Yin and Yang, causing them to interact and conflict, resulting in these symptoms.
Shenzhai (Hu Shenrou) said: In Shanghan (Cold Damage), alternating chills and fever are due to pathogens located at the half-exterior and half-interior level; internal injury-induced alternating chills and fever are due to dual deficiency of Qi and Blood. Qi deficiency leads to fever, while Blood deficiency leads to cold. Any fever on the muscle surface is caused by excess pathogenic Yang and deficiency of healthy Yang (True Yang). The use of Huangqi (Astragali Radix) and Fuzi (Aconiti Lateralis Radix Praeparata) is to assist Yang. Since Yang Qi is already deficient, Huangqi has a mild nature and cannot reach the exterior; it requires the vigorous energy of Fuzi to guide Huangqi directly to the surface to aid in treatment success.
The Ling Shu states: If the Spirit (Shen) is injured by excessive thought, muscles will waste away; if the Intention (Yi) is injured by sorrow, limbs will become useless; if the Ethereal Soul (Hun) is injured by grief, sinews will contract; if the Corporeal Soul (Po) is injured by excessive joy, skin will become dry; if the Will (Zhi) is injured by intense anger, the waist and spine will be difficult to bend or extend.
Mr. Chu's chapter on Essence and Blood states: When a man's essence is not yet unblocked, engaging in intercourse to release his essence will leave the five bodies incomplete, leading to difficult-to-describe illnesses later in life. If the penis is flaccid but one still desires sexual imagery to ejaculate, the essence will not exit but rot internally, causing the urinary tract to become obstructed, resulting in Lin syndrome (dysuria); if essence is already depleted but further exhausted, both the large and small bowel tracts will pull and hurt; the more it hurts, the more one desires to urinate, and the more one urinates, the more it hurts. It also states: Once a woman's Tian Gui (menstruation) arrives, if she does not have intercourse with a man for over ten years, her menstruation will be irregular; if less than ten years have passed but she desires intercourse, her menstruation will also be irregular. Irregularity means old blood does not exit, and new blood flows erroneously, sometimes ulcerating into the bones, sometimes turning into swelling, or even if intercourse occurs, conception may be difficult. Excessive intercourse depletes essence, weakening the person; frequent childbirth depletes blood, potentially causing death. Observing the depletion of essence and blood reveals much about health. (Note: The text implies menstrual water originates from the surplus of Jing and Blood.) Menstrual water is formed from the residual Qi of the meridians. If there is no external invasion by the Six Evils (Wind, Cold, Summerheat, Dampness, Dryness, Fire) and no internal injury by the Seven Emotions (Joy, Anger, Worry, Thought, Sorrow, Fear, Fright), and the Qi of the Spleen and Stomach is strong, then the Qi of the Chong and Ren vessels will be abundant, so menstruation will arrive on time. However, some people have sallow complexion, emaciated limbs, fever, dry mouth, delayed and scanty menstruation. This is insufficient Yin Blood, not a pattern of excess stasis blocking the channels. One should use formulas that nourish Qi and Blood to gradually tonify, making the menstrual Qi strong so that menses naturally flow on time.
It also states: For palace maids released from service and young widows over thirty who experience pain in both hips without skin swelling or color change, or who experience dysuria-like symptoms especially painful during defecation, this is harm caused by blood stasis infiltrating the tunnels (lower jiao meridians or urethra), a condition resulting from lack of male-female union. (If stasis infiltrates the intestines and stomach, it forms Xue Gu [Blood Distension]. The Classics state: Abdominal distension with pus and blood outside the intestines/stomach, accompanied by obstructed and severely painful urination, should not be treated as a water-dampness disorder.)
Zhu Danxi said: The Kidney governs closure and storage, while the Liver governs dispersion and excretion. Both organs contain Ministerial Fire (Xiang Huo), which connects upward to the Heart. The Heart is the Sovereign Fire (Jun Huo) and moves easily when affected by external objects. When the Heart moves, Ministerial Fire rises spontaneously following it; even without intercourse, essence is secretly consumed.