The moon was universally admitted under the theory of the macrocosm
and the microcosm to rule the head, and as silver was the recognised
representative of Luna among the metals the deduction was obvious that
silver was the suitable remedy for all diseases affecting the brain,
as apoplexy, epilepsy, melancholia, vertigo, and failure of memory.
Tachenius relates that a certain silversmith had the gift of being
able to repeat word for word anything that he heard, and this power
he attributed to his absorption of particles of silver in the course
of his work. It does not appear, however, that all silversmiths were
similarly endowed.
The Greek and Latin doctors make no allusion to silver as a medicine,
and the earliest evidence of its actual employment as a remedy is found
in the writings of Avicenna, who gave it in the metallic state “in
tremore cordis, in fœtore oris.” He is also believed to have introduced
the practice of silvering pills with the intention of thereby adding
to their efficacy. To John Damascenus, a Christian saint who lived
among the Arabs before Avicenna, is attributed the remark concerning
silver, “Remedium adhibitum est, et in omnibus itaque capitis morbis,
ob Lunæ, Argenti, et Cerebri sympathicam trinitatem.” This association
of the moon, silver, and the brain was believed in firmly by the
chemical doctors of the sixteenth century, and for a long time a
tincture of the moon, tinctura Lunæ, was the most famous remedy in
epilepsy and melancholia. A great many high authorities, among them
Boyle, Boerhaave, and Hoffmann in the eighteenth century, continued
to prescribe this tincture or the lunar pills, but silver gradually
dropped out of fashion. A great number of medical investigators since
have from time to time recommended the nitrate or the chloride of
silver in various diseases, but without succeeding in securing for
silver a permanent reputation as an internal medicine.
The Pilulæ Lunares were generally composed of nitrate of silver
combined with opium, musk, and camphor. Nitrate of silver was given in
doses varying from a twentieth to a tenth of a grain. The tincture of
the moon was a solution of nitrate of silver with some copper, which
gave it a blue tint and probably was the active medicinal ingredient.
Fused nitrate of silver or lunar caustic seems to have succeeded to
the reputation of fused caustic potash as a cautery, and also to
have acquired the name of lapis infernalis (sometimes translated
“hell-stone” in old books) originally applied to the fused potash.
The only reason assigned for this title is the keen pain caused by the
application of the caustic, though probably it was first adopted to
contrast it with the lapis divinus, which was a combination of sulphate
of copper and alum used as an application to the eyes.
Christopher Glaser, pharmacien at the court of Louis XIV, who
subsequently had to leave France on suspicion of being implicated in
the Brinvilliers poisonings, was the first to make nitrate of silver in
sticks.