Those who are interested in Taoist alchemical language and its deeper meanings must look into the symbolic words and figure out the hidden meanings behind the cryptic and difficult to fathom symbols and phrases. Hearing ideas like "heaven" and "earth","fire" and "water", "lead", "mercury", "tiger" and "dragon", "jade furnace", "medicine", the "mysterious pass", "golden elixir", the "immortal embryo", and the "gate of no gate" one must not think such words refer to the preparation of chemical potions to ingest or parts of the body, but remember that these words and phrases are symbols. They use a language which speaks of one thing to allude to another.
Fire and Water
The concepts of "fire" and "water" do not refer to actual fire and water. They are symbolic of deeper sides of our nature. The fervor and impetuosity of people is passionate and volatile and so it is referred to as fire. The other side of people's character, the calm, centered, more contained and wise side is steady and careful. It has a more settled quality, a "softness", a "flexibility" which contrasts with the fiery and volatile side, and so it is referred to as water. Using the more contained and settled "water" side is using thoughtfulness, logic, and control to nurture and guide our more impulsive and wild side. Using the other side of our disposition, the excitable and temperamental "fire" nature, to complete and balance the often too staid and overly controlling "water" nature is allowing that side of our character expression. By finding a balance between these two sides of our makeup we become more complete and whole.
Lead and Mercury
The ideas of lead and mercury use the ideas of "lead", which is heavy and dense, and lasts a long time without disintegrating, and "mercury" which is lively, active, and doesn't last a long time, to refer to states of mind. What is called "lead" in the alchemical texts is not ordinary material lead but the deep rich sense of true knowledge. This true knowledge is solid, deep, long-lasting and unbending like the sense one gets from "lead". What is called "mercury" in the alchemical texts refers not to actual material "mercury", but to the yin aspects of reality's nature; the side which is pliant, effervescent, spontaneous, unfathomable, and metaphysical. Because it is difficult to pin down and is formless and elusive this aspect of reality and consciousness is likened to mercury.
The Tiger and the Dragon
Alchemical language, when speaking of the "tiger" and the "dragon", in most cases refers to either of two basic considerations. It means either the "tiger" as the physical aspects of life and the "dragon" as the spiritual aspects -- these are sometimes called the ordinary tiger and ordinary dragon. However, the terms are also used to refer to the non-ordinary aspects, or the aspects such as those of the conditioned consciousness and the emotionally obsessed or illusioned consciousness in relation to the evolved consciousness which has learned to transcend the "ordinary" states of being conditioned or being emotionally obsessed. When, through the self-cultivation work, one refines away the conditioned temperament and the obsessing emotional habits and feelings, then the "ordinary" tiger and dragon are overcome, and the "true tiger" and "true dragon" of primordial essence arise. When this happens a clarity is awakened which is so clear and fundamentally beautiful that it seems like a bright light or a shining "mystic" pearl. When this clarity is firmly in place it pervades the universe without hindrance.
The Jade Furnace
The "jade furnace" is symbolic language for the "container" or "field" within which the work of self-cultivation and empowerment takes place. It is called "jade" because the mellow and beautiful tones of jade are like the calm serenity and steady going quality of the work.
The term "furnace" is used because it evokes the idea of slow cooking or slow evolution, just as one slowly evolves and changes when one applies oneself diligently and perseveringly in self-cultivation practice. The jade furnace does not refer to some specific place in the body. It would be a mistake for people to conceive of it in such a manner. One must go deeper than such surface approaches.
Medicines
The "medicines" of alchemical language don't refer to physical medicines one should take into one's physical body, but to the medicines of real inner knowledge and conscious and conscientious practice. Ideas of yin, yang, subtlety, sensitivity, quietude, tranquility, perseverance, balance, evenness, honesty, sincerity, patience, simplicity, objectivity, etc. are the real "medicines". To think that the terms alchemical "medicines" or spiritual medicines refer to mundane physical substances is to fall way short of proper and deep understanding.
The Mysterious Pass
The mysterious pass is profoundly subtle. It is not an ordinary aperture or place of the body which has shape and form and can be pointed to. The mysterious pass is immaterial and formless, and is without physical location. It is where essence and life abide. It is the intangible which connects with the primordial source. It is called the opening of the mysterious female, the door of birth and death, the commencement of non-being, and the great valley, yet all these terms refer to a basic immaterial quality of consciousness which has to do with reaching open and vital spiritual essence. Proceeding rightly it could be called objectivity. Proceeding wrongly it could be called obsession. Proceeding rightly it could be called clarity. Proceeding wrongly it could be called aloofness. Proceeding rightly it could be called balance. Proceeding wrongly it could be called illusion.
The mysterious pass is the access way which leads to the stabilization and preservation of essence and life.
The Golden Elixir
When one's self-cultivation conforms to what is appropriate for the times and circumstance, the real can solidify, the false can disperse, and the "golden elixir" can crystallize. To undo the false and establish the real is to open up the conditions for the golden elixir. It is possible to evoke the realness of the golden elixir, and not actually recognize it, however, due to delusions, personal and cultural agendas, and bias. When the golden elixir is established and recognized, true blissful tranquility settles in place and the calmness of autonomous and non-personal knowing is attained. The golden elixir is called golden because it is even, shining, and mellow like the quality of real truth. It is called the elixir because it is the fountainhead and source of all that is real, genuine, and actual.
The Immortal Embryo
After birth the fundamental and original essence is without knowledge, yet it is full. As life progresses, as knowledge is gained, that fundamental primordial essence generally becomes seduced and distorted by external influences. The cycle of life rises and one moves away from original sense and imbalance and delusion replaces true original autonomous wholeness. Yet if one follows the course of self-cultivation assiduously, on can turn around the situation and regain the vitality, wholeness, and bliss of original fundamental essence. Too often people cannot recognize true unblemished sense; they mistakenly take physical locations in the human, earthly, or heavenly body as places which will help them regain the fundamental source and harmony. They indulge in bogus practices in efforts to once again establish their original "face". They look to the abdomen, the torso, or the head as places where the immortal embryo should reside. They go through complicated fantasies and mental gyrations, fooling and deluding themselves. It is no wonder such people struggle all their lives , only to grow into old age without attainment.
The immortal embryo is not a physical entity. It is a state of consciousness. It is called an embryo because if one attains it one regains the simplicity and clarity of an infant. It is called immortal because the state of mind to which it refers is the universal and undying essence which hasn't changed since the beginning of time and will never change. It is called the embryo because it is a "second beginning" which parallels one's physical birth -- yet now takes place on the spiritual and psychological plane -- it is the beginning of one's true, undiluted life. It is called immortal because when one contacts it, one contacts that which all enlightened beings since time immemorial have realized. To live in contact with it is to live in contact with that which is significant at all times and all places. To regain it one must come face to face with that which is nameless and void. One must know reality without the filters and buffers of fantasy and bias. One must not be too much or too little, one side or the other, too up or too down, too full or too empty. One must be absolutely precise and without tendency -- a million times sharper than a razor's edge. Then, following the course of nature, the immature can mature and what has been lost can be regained again.
In the end, the path of Alchemy is simply a spiritual path. Being a spiritual path, it must be a path of "realness". To follow such a path is to follow practices which help one to remain authentic and true to oneself and to the original source of all things. To follow such a path is to eschew delusion and acculturation. It is to know the path of the universal, the path of yin and yang, the whole path of the heart and rationality as one, and the path of nature. To cleave to the course of usual conditioning is to be ensconced in the mundane which doesn't know its own beauty. To cleave to the course of usual conditioning is to miss being an "enlightened and empowered immortal being".