Ramon Llull, a renowned alchemist, surgeon, scholar, doctor, and Catholic priest, authored "On the Secrets of Nature." This exceptional work serves as a guide to extracting the quintessence and medicinal properties from nature. Llull's book meticulously details the creation of alchemical stones, showcasing his profound understanding of the alchemical arts. It stands as one of the finest examples of early medieval literature from the 1200s, providing invaluable insights into the practices and knowledge of the time. With its focus on the extraction of quintessence and the creation of medicinal substances, this work embodies Llull's expertise and represents a significant contribution to the field of alchemy and medicine. "Or by turns, it will exempt you from all the labor of solutions and coagulations. The reason is that this is the hidden oil that makes medicine penetrable, friendly, and capable of joining with all bodies, and it acts more effectively in this manner, so that there is nothing more secret in the world. Therefore, I say wondrous things that would be incredible to all ancient philosophers, namely that if you know how to separate this well from its watery nature and work with it according to the given method of mixing, you can compose the stone in thirty days. However, this oil is not necessary in the vegetable realm by itself, as solutions and coagulations there, as mentioned, occur quickly, but if sublimation occurs there, I believe the tincture of the stone will greatly expand. I do not think there are any further instructions that I have not disclosed to you in this short letter. Therefore, choose your purpose from it, praising God, who lives forever and ever. Amen."