鳞虫三百六十，而龙为之长，感水运而生。水者，至阴也。阴极阳生，故戊癸合而化火，火生于水
也。（玉师曰∶龙身有火。）是以鱼属火，而有水火相济之功。
介虫三百六十，皆具坚甲之象，感金气而生，金生水也，外刚内柔，离之象也。故蚌蛤之肉皆主清
凉，在外之壳，又能燥湿，是一物而有水火寒热之分焉。非惟蚌蛤之为然也。如坎为水，水生木，其于木
也，为坚多心，是木皮之清凉者，其心则热。又非惟木之为然也。凡物之极寒者必有热，极热者必有寒，
盖物极则变，变则生化。玉师曰∶如麻黄大发汗，而根节又能止汗；西瓜大凉，而子性大热。
肾藏精，其荣在发；心主血，发乃血之余也。夫血乃所生之精汁，奉心神而化赤，故曰血者神气也。
本经发 ，主五癃关格不通，疗小儿惊，大人痉，仍自还神化，谓血化之余荣，仍自还于神化也。血脉
流通，精神交感，则关格通而惊痉自解。是以痘方用血余者，取其能导肾精中之毒瓦斯，归于心神，行于脉
络，而又能败毒。
李时珍曰∶龟、鹿皆灵而有寿。龟首常藏向腹，能通任脉，故取其甲，以补心、补肾、补血，皆以养
阴也。鹿鼻常反向尾，能通督脉，故取其角，以补命、补精、补气，皆以养阳也。乃物理之玄微，神工
之能事。按任脉起于中极之下，以上毛际，循腹里，上关元，至咽喉，上颐循面。督脉环绕一身，循腰
脊，历络两肾。龟板治小儿囟不合，鹿茸主生齿不老，盖二品皆属于肾，肾主骨也。任、督二脉，为阴
阳百脉之宗，又皆出于肾。故痘方用之者，一取其养
阴而清热，一取其透顶以败毒，导肾中之火毒，从百脉而外出于皮肤。（龟板又能达于四肢，故主治四肢重弱，
上古卜蔡烹而用之，若败龟板者，乃病死枯败之物，绝无灵气，又何所取焉？）
There are three hundred and sixty species of scaled creatures (Lin Chong), among which the dragon is their leader, born by sensing the movement of water. Water belongs to extreme Yin. When Yin reaches its extremity, Yang is generated; thus, Wu and Gui combine to transform into Fire, meaning Fire is born from Water. (Master Yu said: The body of the dragon contains Fire.) Therefore, fish belong to Fire and possess the function of mutual assistance between Water and Fire.
There are three hundred and sixty species of shelled creatures (Jie Chong), all possessing the image of hard armor, born by sensing Metal Qi. Metal generates Water; they are rigid on the outside and soft on the inside, corresponding to the image of the Li trigram. Thus, the flesh of clams and mussels is primarily cool and clearing, while their outer shells can dry dampness. One substance possesses distinctions of Water/Fire and Cold/Heat. This is not limited to clams and mussels. For instance, Kan represents Water, and Water generates Wood. Regarding Wood, it manifests as "hard with a soft core," implying that while the bark of wood is cool, its core is hot. This applies not only to Wood. Generally, things that are extremely cold must contain heat, and those that are extremely hot must contain cold. This is because when things reach an extreme, they change; upon changing, new generation and transformation occur. Master Yu said: For example, Ephedrae Herba (Mahuang) induces profuse sweating, yet its root nodes can stop sweating; Watermelon is greatly cooling, but its seeds are greatly heating.
The Kidney stores Essence, and its flourishing aspect manifests in the hair; the Heart governs Blood, and hair is considered the surplus of Blood. Blood is derived from the essence fluids produced, transformed into red by the spirit of the Heart; thus, it is said that Blood is Spirit Qi. The *Ben Jing* records that Hair Remainder (Xueyu) treats five types of strangury and obstruction due to Guan Ge syndrome, cures pediatric convulsions and adult spasms, and still returns to spiritual transformation. This means the surplus flourishing derived from Blood transformation still returns to the transformation of Spirit Qi. When blood vessels flow smoothly and spirit and qi interact mutually, the obstruction of Guan Ge clears, and convulsions and spasms resolve spontaneously. Therefore, in formulas for smallpox, Hair Remainder is used to guide the toxic vapors from Kidney Essence to the Spirit of the Heart, circulate through the collaterals, and defeat toxins.
Li Shizhen said: Both the turtle and the deer are spiritual and long-lived. The turtle's head is often tucked toward the abdomen, connecting with the Ren Mai (Conception Vessel); thus, its shell is taken to tonify the Heart, Kidney, and Blood, all serving to nourish Yin. The deer's nose is often turned back toward the tail, connecting with the Du Mai (Governing Vessel); thus, its horn is taken to tonify the Mingmen (Gate of Life), Essence, and Qi, all serving to nourish Yang. These are profound subtleties of physical principles and feats of divine craftsmanship. According to texts, the Ren Mai originates below the Zhongji point, ascends past the pubic region, follows the interior of the abdomen, ascends to the Guanyuan point, reaches the throat, goes up to the chin, and follows the face. The Du Mai surrounds the body, follows the waist and spine, and interlaces with both Kidneys. Turtle Shell (Guiban) treats unclosed fontanels in children; Deer Antler Velvet (Lurong) promotes tooth growth and prevents aging. Both substances belong to the Kidney, which governs bones. The Ren and Du meridians are the ancestors of all Yin and Yang meridians and both originate from the Kidney. Hence, in smallpox formulas, they are used: one to nourish Yin and clear heat, the other to penetrate the vertex to defeat toxins, guiding the fire-toxin from the Kidney outward through the hundred meridians to the skin. (Turtle Shell can also reach the four limbs, thus treating heaviness and weakness in the limbs. In ancient times, tortoises used for divination were boiled and used; however, dead or decayed turtle shells lack spiritual energy entirely, so what value do they hold?)