Johann Konrad Dippel was a German alchemist, physician, and theologian [1,2]. He co-developed a process for the production of Prussian blue, a widely used pigment. He also produced “Dippel’s animal oil” from dried beef blood, which was used, e.g., as a remedy for different diseases and as an animal and insect repellent, as well as hartshorn, which has applications as both a smelling salt and a leavening agent for baking—both with significant commercial success.
1 Dippel’s Life
Johann Konrad Dippel was born at Castle Frankenstein near Mühltal, Germany (then Holy Roman Empire of the German Nation), on August 10, 1673. He studied philosophy and theology at the University of Gießen, Germany, and then worked as a teacher at first. In 1704–1707, Dippel worked as an alchemist in Berlin, trying to convert silver and mercury to gold.
Dippel had become a radical pietist around 1697 and published controversial polemics, which ultimately got him arrested in 1707 and led him to flee to Holland. There, he completed a doctorate in medicine in Leiden in 1711 and then worked as a physician/chemist.
From 1714 to 1717, Dippel lived in Altona (today a part of Hamburg, Germany) which was Danish at the time, until he was sentenced for defamation of a senior government official and spent seven years as a prisoner on the Danish island of Bornholm. He was released at the request of the Queen of Denmark. Starting in 1727, he lived in Stockholm and served as physician to the Swedish court. Johann Konrad Dippel returned to Germany and passed away on April 25, 1734, at Castle Wittgenstein near Bad Laasphe, Germany.
2 Dippel’s Research
2.1 Dippel’s Animal Oil
Repugnant-smelling animal oil (or oleum animale) used to be a home remedy that was found in ointments against typhus and in a turpentine oil mixture to treat tapeworms. Crude, black-brown animal oil was obtained by the destructive distillation of horn, bones, and leather.
Dippel improved the production method by using exclusively dried beef blood and developed a multi-step purification process based on distillations. After many distillations of the crude animal oil, Dippel obtained a visually appealing, pale yellow oil. The smell of Dippel’s animal oil, however, was still bad. Nevertheless, it was a commercial success after Dippel asserted that it would bring back spent vital force, cure every disease, and lead to eternal life.
While animal oil turned out to have no medical effects, its terrible smell still makes it useful: It is rubbed on horses to ward off insects, can be used to prevent tail biting in pigs and the tearing out of feathers in fowl, and can help to protect fields from damage by wild animals.
Hartshorn primarily consists of ammonium hydrogen carbonate (NH4HCO3) with small amounts of ammonium carbonate ((NH4)2CO3) and ammonium carbamate (H2NCO2NH4). The sharp ammonia odor of hartshorn makes it useful as a smelling salt, causing people to quickly regain consciousness after fainting. It can also be used as a leavening agent for baking.
Hartshorn was traditionally made from grated stag horn, hooves, and claws through dry heating. Dippel optimized the production process by heating a mixture of dried beef blood and potash to sublime out the volatile hartshorn. It was another commercial success for Dippel.
2.3 Prussian Blue
Dippel allowed guests to use his laboratory. One of these guests was a Berlin-based pigment merchant named Lieutenant Johann Jacob von Diesbach. Diesbach traded dyes and pigments that he partially produced himself in Dippel’s laboratory—in particular, Florentine lake, a pigment made from the Mexican cochineal insects. The shade of the Florentine lake could be changed within certain limits by the addition of metal salts. Iron salts, for example, make it purple.
One day in 1706, Diesbach obtained a deep blue paint pigment instead of purple Florentine lake. This was due to a serendipitous mistake: Dippel and a colleague had produced a large amount of hartshorn, leading to several pounds of residue from the dried beef blood. The residue was leached out and the resulting solid was stored in a container labeled “potash”. Diesbach used the “potash” from this container aiming to make Florentine lake, but obtained Prussian blue instead. As it turns out, the residue, which had been processed at high temperatures, contained potassium cyanide, with the potassium stemming from potash and the cyanide from decomposition of the protein in the beef blood. The KCN then formed Prussian blue, or FeIIIK[FeII(CN)6], together with the iron present in the reaction mixture.
Diesbach and Dippel developed a production process for the new blue pigment. The new blue pigment quickly became popular among painters and was named “Berlin blue”. This name is still used in German-speaking countries. In English, the pigment is called Prussian blue. Artists used it instead of the extremely expensive ultramarine—thus, demand was high, and the production was very lucrative for Dippel and Diesbach, who kept the production process secret until it was leaked in 1724.
3 Sidenote: Dippel and Mary Shelley’s Frankenstein
It has been hypothesized that Johann Konrad Dippel was the model for the scientist in Mary Shelley’s novel Frankenstein; or, The Modern Prometheus, published in 1818 . The scientist, Victor Frankenstein, develops a method to give life to inanimate matter, and uses it to bring a humanoid body created out of deceased body parts to life: the famous Frankenstein’s monster, or “the Creature”.
According to a local historian, when Jacob and Wilhelm Grimm were collecting their famous fairy tales, they heard a horror story about Johann Konrad Dippel von Frankenstein from the pastor of a village near the castle: He told them of the corpse robber and grave desecrator Dippel, who wanted to create a new human being from corpse parts and the blood of virgins. Jacob Grimm supposedly retold this story in a letter to the English translator of the fairy tales, Mary Jane Clairmont, who was the stepmother of Mary Shelley. Shelley may also have visited the castle during her travels. However, this connection between Dippel and Shelley remains controversial among historians due to a lack of concrete evidence.
Johann Konrad Dippel is the answer to Guess the Chemist (140).
 Mary Shelley, die Burg und das Monster,
www.frankenstein-restaurant.de. (accessed August 9, 2023)
Also of Interest
Prussian Blue: Discovery and Betrayal,
Around 1700, Berlin was a colorful center of innovation – a scene that led to the discovery of the century: Prussian blue – the article looks, e.g., at how Johann Konrad Dippel almost ruined the Prussian blue business