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？）
鳞类动物共有三百六十种，其中龙是它们的首领，感应水的运行而生成。水，属于至阴之物。阴气达到极致则阳气产生，所以戊癸相合化为火，火是从水中产生的。（玉师说：龙的身体带有火性。）因此鱼类归属于火，具有水火相互济助的功效。
介类动物（有甲壳的动物）共有三百六十种，都具备坚硬外壳的形态，感应金气而生，金能生水，它们外表刚硬而内部柔软，符合离卦的象意。所以蚌蛤的肉都具有清凉的特性，而外部的壳又能燥湿，一种物体却包含水火、寒热不同的属性。不仅仅是蚌蛤如此。比如坎卦代表水，水生木，对于木来说，表现为“坚多心”（木质坚硬且中心部分性质不同），这意味着木皮是清凉的，而其中心则是热的。也不仅仅是木如此。凡是物性极寒的必然含有热性，极热的必然含有寒性，大概是因为事物发展到极端就会变化，变化了就能产生新的生化作用。玉师说：比如麻黄发汗作用强烈，但其根节却能止汗；西瓜大凉，但其子的性质是大热的。
肾藏精，其华表现在头发；心主血，头发是血的剩余部分。血液是由所生之精汁转化而来，奉心神之气而化为红色，所以说血就是神气。《本经》记载头发（血余）主治五种小便不通及关格病导致的气机阻滞，治疗小儿惊风、成人痉挛，仍能自我返还并促进神气的化生，意思是血化生的剩余荣华，仍能自我返还于神气的化生之中。血脉流通，精神交感，那么关格阻滞就会通畅，惊风和痉挛自然解除。因此痘科方剂中使用血余，是取它能引导肾精中的毒瓦斯，归于心神，运行于脉络，并且能够败解毒邪。
李时珍说：龟和鹿都有灵性且长寿。龟头常常缩向腹部，能通任脉，所以取它的甲，用来补心、补肾、补血，都是为了滋养阴液。鹿鼻常常反向指向尾巴，能通督脉，所以取它的角，用来补命门、补精、补气，都是为了滋养阳气。这是物理中玄妙微细的道理，也是神奇工巧所能达到的境界。按任脉起于中极穴之下，向上经过阴毛际，沿着腹腔内部，上行至关元穴，到达咽喉，上颐部循行面部。督脉环绕全身，沿着腰脊，联络两肾。龟板治疗小儿囟门不合，鹿茸主治牙齿生长及延缓衰老，因为这两味药都属于肾，肾主骨。任脉和督脉，是阴阳各条经脉的宗主，又都起源于肾。所以在痘科方剂中使用它们，一是取它滋养阴液以清热，二是取它透达头顶以败毒，引导肾中的火毒，从百脉向外发散到皮肤。（龟板又能通达四肢，所以主治四肢沉重无力，上古时代占卜用的龟被烹煮后使用，如果是病死枯败的龟板，完全没有灵气，又有什么可取的呢？）
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?)