The bean of Physostigma venenosum.—Africa.
Preparations.—Tincture of Physostigma. Extract of Physostigma. Eserine.
Dose.—The dose of a tincture of the strength of one ounce of the bean to two ounces of tincture will range from the fraction of a drop to five drops. The dose of Eserine is from 1-60 to 1-20 of a grain; it is applied to the eye in a solution of one part to one thousand.
Specific Indications.—In ophthalmic medicine it is indicated by too great dilatation of the pupil (usually the result of atropia), mydriasis. In its internal administration, it may sometimes be indicated by dilated pupil, but generally by contraction of pupil, tense, small, and rapid pulse, and sense of constriction of chest with difficult breathing. The entire facial expression shows great irritation of the spinal and superior sympathetic nerves.
Therapeutic Action.—Attention was called to the Calabar Bean by its use by the natives in the "ordeal" to determine the guilt or innocence of a party charged with crime. Denying his guilt, he was allowed the privilege of taking the "ordeal bean," and if he survived its action, was declared innocent of the crime. It was always given in quantities sufficiently large to produce death, but in some cases the stomach rejected it, or it was passed off by the intestinal canal without being absorbed.
In the experiments of Dr. Fraser the effects seemed principally upon the spinal cord. "They were paralysis, loss of reflex action, contraction of the pupil, occasionally evacuation of the bowels, with retention of consciousness until all power of expression ceased." "Dr. Christison took about twelve grains of the kernel, which, in fifteen minutes, produced giddiness and a feeling of torpidity, followed by great weakness and faintness, paleness of the surface, extreme weakness and irregularity of the pulse, and indisposition or inability to make voluntary muscular effort."
The effects described by Dr. Christison (a most reliable observer) will point out the uses of this remedy. Here is the direction of the force, and when in disease such action will appease disease, we will select this agent. If the reader will notice, it produced a "feeling of giddiness and torpidity;" it therefore diminishes innervation from the brain and spinal cord, and is to be used when we have undue excitement from these centers. "Followed by weakness and faintness"—the same action, but influencing the muscular system, and especially that function which we know as reflex action. This is further strengthened by the record, "inability to make voluntrary muscular effort." "Extreme weakness and irregularity of pulse," with paleness of the surface, shows its action upon the vascular system.
I have employed the remedy in a few cases of convulsions. In two cases of puerperal convulsions the effect was all that could be desired. In one case of infantile convulsions which the common remedies failed to control, its action was prompt and curative. I gave it in one case of epilepsy with apparently good results, but the patient removed from the city, so that the experiment was not satisfactory.
It is thought that Physostigma holds the first place in the treatment of tetanus, and a large number of cases are on record in which it has proven curative. In this case the dose of the extract should be as much as one-third of a grain, repeated sufficiently often to get its relaxant effect. It has been suggested in the treatment of poisoning by strychnia, but further evidence is required to show its antidotal powers.
Physostigma or Eserine is employed in ophthalmic medicine to cause contraction of the pupil after dilatation with atropia. When adhesions of the iris are feared, alternate dilatation by atropia and contraction by calabar bean are resorted to to break them down or prevent them.