Robert Christison (1797–1882), Ludwig Laqueur (1839–1909), Thomas Fraser (1841–1920), Mary Walker (1888–1974)
TRIAL BY BEAN. Physostigmine, the first effective drug found for the treatment of glaucoma in 1875, has a far earlier history in trials for witchcraft in West Africa. The accused was compelled to ingest seeds of the Calabar bean to assess guilt. If the ingestion was slow and hesitant, symptoms of poisoning appeared as evidence of guilt. By contrast, innocent individuals would presumably eat the beans rapidly, which caused them to vomit and purge the poison from their bodies.
A professor of materia medica, Robert Christison of Edinburgh first scientifically sampled the beans in 1855 and almost died as a result. In 1863, his distinguished pupil Thomas Fraser tested extracts of the bean on many body tissues and organs, including the pupil, and proposed its use in ophthalmology. The following year, the active chemical in the bean, physostigmine (an alkaloid, also termed eserine after the West African designation of Calabar bean) was isolated. In 1875, Ludwig Laqueur, a German ophthalmologist who suffered from glaucoma, showed physostigmine to be effective in treating the disease.
In glaucoma (a leading cause of vision loss and blindness in adults older than forty), increased pressure within the eye damages the optic nerve. Physostigmine increases the outflow of aqueous humor from the eye, thereby reducing the intraocular pressure. In recent decades, many more longer-acting drugs that cause fewer adverse effects have replaced physostigmine as an eye ointment.
In 1934, the Scottish physician Mary Walker discovered that an injection of physostigmine could temporarily restore muscle strength to patients with myasthenia gravis, but it was replaced with the more effective neostigmine a year later. Organophosphate nerve gases such as tabun and sarin—the most deadly chemical warfare agents—act in a manner similar to physostigmine.
SEE ALSO Alkaloids (1806), Neostigmine and Pyridostigmine (1935), Tabun and Sarin (1936), Diamox (1953), Timoptic (1978).
Physostigmine treats glaucoma by reducing intraocular pressure. Here, illustrations of the eye are exhibited in Brockhaus and Efron Encyclopedic Dictionary, published in Imperial Russia between 1890 and 1907.