The Mystery Of Causticum
John Morgan M.R.Pharm.S
Introduction
The development of remedies has been very prolific since Hahnemann developed his first 70
remedies, and, on the whole, the preparation of most remedies is quite straightforward and well
documented. Homoeopathic pharmacy is a science of mimicry and the various pharmacopoeias
and ancient texts provide the guidelines needed to create a remedy which mirrors the original
proving. Apart from the difficulty of obtaining the raw materials for some rare remedies, such as
nosodes, tincture making from medicinal herbs and trituration of elements and inorganic
materials is a long but basically uncomplicated process. Even the imponderabilia, such as the
Magnetic Poles, Sol, Luna and X-Ray are quite easy to make. However there is a special group of
unique remedies which Hahnemann developed himself which present there own challenges. They
are Calc Carb, Hepar Sulph, Merc Sol, Silica and Causticum - the so-called Hahnemannii remedies.
The first two are related by the use of the shell from the european edible oyster, Ostrea Edulis, as
a source of calcium carbonate. It seems, from Hahnemann's experiments, that there was a
shortage of pure chemicals and the preparation of lime water (calcium hydroxide Ca(OH)2
solution) so often used in chemistry, was procured from impure calcium carbonate sources. In an
early formula of Merc Sol, given in lesser writings, he uses burnt egg shells to make lime water.
Hepar Sulph is an impure calcium sulphide and is made by putting an equal parts mixture of
powdered oyster shell and pure flowers of sulphur in a sealed porcelain crucible and heating to
white heat for 10 minutes. The off white powder has an odour of hydrogen sulphide (rotten eggs)
and is insoluble so is triturated to potency.
Merc Sol was created by Hahnemann in the days before he used potencies. The aim was to
produce a palatable form of mercury which could be absorbed into the body easily as existing
mercurial medicines were so poisonous and particularly corrosive. The 'solubilis' part of its name
refers to its easy solubility in gastric acids and absorption by the stomach when ingested and not
to its physical properties. The complicated Merc Sol formula of 1788, given in the preface to lesser
writings, dissolves mercury metal in nitric acid and precipitates out the insoluble black dimercurous
ammonium nitrate. 2(NH Hg2) NO3H2O by the addition of ammonia. The resultant
insoluble black powder is washed and triturated to potency.
Silica is made by melting one part of clean white sand, or rock quartz, with four parts sodium
carbonate. The resulting glassy mass is pulverised and dissolved in water to release the silica as a
precipitate which is then washed many times to free it from sodium salts. Presumably this
formula was developed because pure silica was not available in the early 1800's so Hahnemann
had to make it himself
Silica is made by melting one part of clean white sand, or rock quartz, with four parts sodium
carbonate. The resulting glassy mass is pulverised and dissolved in water to release the silica as a
precipitate which is then washed many times to free it from sodium salts. Presumably this
formula was developed because pure silica was not available in the early 1800's so Hahnemann
had to make it himself.
And finally to Causticum which is without doubt the most challenging of them all. I have made
this remedy five times in the last eleven years with three successes and two complete failures. It
demands skill, great care and patience and compels the pharmacist to heed the great master's
words 'follow me, but follow me well'. It is by far the most complicated and involved process of
all Hahnemann's special remedies, involving hazardous chemical reactions and distillation
apparatus which needs constant care and attention. Making Causticum is an experience which is
different every time and has been a deep learning experience for me personally. It is also the only
one of these remedies for which the final chemical composition has been the subject of debate and
it is still not known what Causticum actually is. Even before Hahnemann's death it was
controversial. In 1835 a chemist called Griesselich followed Hahnemann's instructions to the letter
but failed to reproduce the remedy concluding that there was no such thing as Causticum. He
offered a prize of 12 ducats to anyone who could clarify its chemical nature - an offer which was
not taken up by anyone. The recorded attempts of other chemists, during Hahnemann's lifetime,
and the analysis of different preparations from different manufacturers, more recently, has
revealed variable and inconclusive results. Also, as I shall explain later, chemically there are good reasons why it should be nothing other than distilled water which was what Griesselich's
experiments mostly produced.
To try and unravel this mystery we must look at the preparation in detail, in the Causticum
monograph in Chronic Diseases. I will go through it step by step to explain the chemical changes.
Lime, in the state of marble, owes its insolubility in water and its mildness to an acid of the lowest order
which is combined with it; when heated to red heat the marble allows this acid to escape as a gas.
Hahnemann is describing the liberation of carbon dioxide (CO2) from marble when it is heated
and its transformation from a hard insoluble form into a soft and water soluble substance which is
calcium oxide (CaO). His use of the word 'lime' to describe marble relates to limestone, from
which marble is derived and not to the modern chemical definition of 'lime' or 'quicklime' which is
calcium oxide. Carbon dioxide is an acidic gas and will make carbonic acid (H2CO3) when
dissolved in water.
During this process the marble, as burned lime, has received (besides the latent heat) another substance
into its composition, which substance, unknown to chemistry, gives to it its caustic property as well as its
solubility in the water, whereby we obtain lime-water.
From this statement is seems that Hahnemann did not know the chemical composition of calcium
oxide which is formed after heating marble or any other calcium carbonate such as egg or oyster
shells. Calcium oxide is caustic, can create burns on the skin and reacts quite violently with water
giving off much heat creating lime water, a solution of calcium hydroxide Ca(OH)2, which has
alkaline properties.
This substance, though not itself an acid, gives to it its caustic virtue, and by adding a fluid acid (which will
endure fire) which then combines with the lime by its closer affinity, the watery caustic (Hydras caustici) is
separated by distillation.
This passage describes the reaction of the alkaline quicklime with a heated acid to create the
watery Causticum which is recovered by distillation.