Alchemy is a scientific tradition, practiced in many parts of the ancient world. Each culture's manifestation of alchemy has been characterized by a particular set of objectives. One of oldest alchemical documents is called the Emerald Tablet of Egypt. It contains thirteen recipes for creating the philosopher's stone, an unknown substance sought out for its ability to transform base metals into gold and silver. In China, the ancients referred to lien tan, the pill of transformation. Principal among their concerns was immortality. Chinese alchemists ultimately aspired to become transformed into hsien, immortal beings who could shuttle between heaven and earth at will. The ancient Indian word for alchemy was rasayana, the way of mercury. Nagarjuna is revered as the father of Indian alchemy. He wrote the first book of Indian alchemical practices, called the Rasarathnakara. The objective of Indian alchemy was to discipline the body in order to expand consciousness to the point of being able to access any entity in the universe. 
And while each is different from the other, all of these alchemical traditions made use of animal symbols. More precisely, animals did things like helped the alchemist create the philosopher’s stone, change base metals into gold and develop the elixir of life that promoted immortality.
WHAT IS YORUBA ALCHEMY?
In all sincerity, the Yoruba are not known to practice alchemy in the strictest sense of the word. That is, there is no Yoruba equivalent to the philosopher's stone. The Yoruba do not have a process of transmuting base metals into precious ones. There are no Yoruba treatises that we might compare to the Emerald Tablet or the Rasarathnakara. Instead, Yoruba ritual specialists limit the application of their crafts to spiritual empowerment, magical displays and the fulfillment of personal destiny. And while most people are familiar with the activities associated with the babalawo and olorisa, Yoruba ritual specialization also includes herbalists, dream diviners, bone throwers, surgeons, birth attendants, general medical practitioners (gbogbonise) stroke and hypertension healers, bone setters (teguntegun), pediatricians (elewe omo) and pharmacists (lekuleja). In an attempt to examine aforementioned disciplines through the lens of alchemy, let us consider the role of animal symbolism in Yoruba spirituality.
From time immemorial, the Yoruba have considered animals to be totem creatures, imbued with mystic powers. Rodents, fish, mammals and birds are all recognized for their unique, spiritual properties. From an alchemical perspective, animal symbols function as a guide for how human life transforms both internally and externally, if we interpret them with precision.
In an article on animals in Yoruba worldview, Ajibade George Olusola details "the Yorùbá perception of animals with regard to their classification, habitat, and their role and position in religious, political, social, economic, and domestic domains of humans. This leads to an appraisal of relationships that exist between the Yorùbá people and animals in their communities. 
As is the case with all things Yoruba, we can look to the oríkì - praise poetry - of various animals in order to gain a better understanding of their importance to the indigenous worldview. Recitation of oríkì is thought to awaken one’s potential powers. The spiritual world is translated into the human world and directed through strategic recitation of oríkì. They hold the secret of the subject - the principles of its being - and the utterance releases its true power. Oriki, in this way, open channels between beings through which powers can pass and potentials emerge. In the same way that there are oríkì for kingdoms, orisa and individuals, there are also oríkì for animals. Here are a few examples, starting with Etu, the antelope:
The one who has legs painted red with camwood
The one who has thighs with which to touch the dew
Eranko tíí lé tìróò
The animal that put on eyelashes
Eranko tíí wa gònbò
The animal that wears gònbò tribal marks
This antelope oríkì describes its appearance. It mirrors the way the Yorùbá formulate and chant oríkì about human beings. In fact, the oríkì for Etu seem to personify the animal by highlighting its similarities to Yoruba beautification rituals. The antelope's natural marks on its face likened to gònbò tribal marks. Likewise, the use of camwood is synonymous with beautification, as well as spiritual empowerment. In these ways, Etu is praised for its natural beauty.
Òbo, the monkey is another animal considered worthy of oríkì, mainly because of its close resembles to humans:
Òbo akájá lóde
The Monkey that teaches the dog how to hunt
Ògbójú Akítì tíí gbàbon lówó ode
The brave Akítì who seizes the gun from the hunter
Eranko tíí tan ode wògbé sùàsùà
The animal who lures the hunter into the thick forest
The above oríkì shows that animals, like humans, are able to think and plan their activities in advance. Not only that, the monkey is bold enough to seize the gun from the hunter. Furthermore, while it is the duty of the hunter to teach the dog how to hunt, we see from the oríkì that monkey is also capable of teaching the dog how to hunt. Here we see that oríkì of Òbo praise the attributes that are reminiscent of human characteristics.
Also, the leopard, Ekùn has its own oríkì. It goes as follows:
Ekùn, Ògíní omo Ìyáyò
Leopard, Ògíní offspring of Ìyáyò
Leopard who fights fiercely
The animal that eats flesh from the head
The one who has knife in its palm
All attributes in the oríkì of Ekùn praise its powers and heroic character. Here, Ekùn is recognized for its ferocity. By its oríkì, we are to understand that Ekùn is the embodiment of danger. For this reason, Yoruba kings adopt the leopard as their regal totem once they ascent the throne. In the oríkì of Ata (king) Gabriel Osho of Ayede, he is praised for his “hot, dangerous and unlimited power:
Leopard, who scrutinizes restlessly
Who eats fire
Who eats sun
Sango, the orisa of lightening, is one of the few orisa visibly associated with the leopard. Leopard imagery associated with Sango refers to two aspects of his being; royalty and temperament. Sango is an aggressive king, who uses lightning as a destructive and violent force that strikes quickly and devastatingly. Similarly, Ekùn is considered a “hot” animal related to aggressive power, who strikes with merciless speed. An oríkì to Sango informs us this way:
...Strong person, leopard spotted, like Orisa Obaluaiye
Leopard Father of the King of Ede
White sky, sign of richness
Owner of the terrifying thunder waller
Owner of laba [wallets] filled with ase, like seasoned warrior
Leopard on the hill...
In this oríkì, Sango’s iwa (essential character) and violent personality become apparent. The leopard imagery repeated three times reiterates the aggressive and dangerous power associated with him. “The leopard has water, but bathes in blood” is an oríkì for Sango and for Ogun, both of whom share aggressive traits.
In Yoruba ritual space, where oríkì are brought to life, sacred icons, as well as people are often painted with spots. These spots, referred to as finfin, are meant to stabilize sacred space. They “convey transformation and transcendence of worldly entities united with otherworldly forces” (Drewal and Mason 1998:78). John Mason states that “The finfin are often associated with the spots of the leopard,” who is not only able to see in the dark, but as lord of the forest has links to the “other world” and is the “ultimate avatar of transformation” (Drewal and Mason 1998: 78; Drewal and Mason 1997: 346).
Sango is not the only orisa associated with the leopard. Osun, who is revered as the harmonious orisa of sweetness and high standards of excellence, also gives birth to leopards (Thompson 1993: 206-211):
Grant us the destiny of the leopard
In the house of my mother, the river
Royal wives give birth to stalwart leopards
Here, we glimpse Osun as the divine consort, who, in spite of her cool demeanor, gives birth to the firey and tumultuous leopard.
Another feminine force within Yoruba cosmology that makes use of leopard iconography is Gelede. In fact, the leopard is one of the most popular of animal motifs used in Gelede (Lawal 1996: 244). During the annual festival of Odun Gelede, one of the most elaborate of Gelede performances begins with an all night festival, Efe. The highlight of the evening and last performer is the Oro Efe mask. Oro Efe is masculine and aggressive. References to Ogun and warriors are emphatic in his presentation. Here, the leopard image signifies the “sacred leadership of kings, chiefs and priest” and its role as king of the night, played out only through the consent of the female “Mothers” (Drewal and Drewal 1990:101).
Oriki, praising “all-the-powers-that-be,” are sung by the maskers, ending with an oriki featuring Oro Efe’s own worthwhile attributes:
If a child sees a leopard, he will forget all about a matchet
If an adult sees a leopard, he will forget all about a gun
There is no animal like the leopard
I, Alabi, the knower of secrets, am here
Everything is under my control, just as a lion uses its urine to cast a spell in the forest
The elephant is a king among animals
There is nothing like a small snake
I am the senior historian
My father, Osefegbayi, Oseni Logo
Was a force to be reckoned with among Ketu performers
Offspring of Gelede who ascended the throne at Ohori Ile
The one with brass bracelets and anklets
Brass ornaments jingle rhythmically
(Lawal 1996: 125)
The leopard motif here evokes the proverb that says, "The leopard's quiet is not an act of timidity; whoever defies the king will be totally crushed.” (Lawal 1996: 244).
Around the world, alchemists delved deeply into animal symbolism to help them attain their esoteric goals. Within the Yoruba spiritual disciplines, we see how ritual specialists have made use of animal symbolism in order to conceptualize and even facilitate transformation. Thus, Yoruba priests have pursued spiritual expansion as a journey in which they encounter archetypal animal figures. The steps on their journey are paralleled in their rituals, ceremonies and preparation of concoctions. And while they do not aspire to eternal life, nor the transmutation of base metals into gold, Yoruba ritual specialists can be said to incorporate alchemical practices into their sacred arts.
 Cavalli, Thom. Alchemical Psychology. Pg 21-25
 Ajibade George Olusola. ANIMALS IN THE TRADITIONAL WORLDVIEW OF THE YORÙBÁ
 ANN BRISBANE BAIRD. THE SIGN OF THE LEOPARD: LEOPARD IMAGERY IN THE KINGDOMS OF THE YORUBA, THE KINGDOM OF BENIN, AND THE KINGDOM OF DAHOMEY .