CALABAR BEAN AS AN OPHTHALMIC MEDICINE. 481 
informed me that he had seen contraetion of the pupil result 
from the local application of an extract of the ordeal bean of 
Calabar. I resolved to investigate the action of this sub¬ 
stance^ and, above all, to ascertain whether it exerted any 
influence on the accommodation of the eye. With some 
difficulty I got a few Calabar beans, and, with the view of 
obtaining their active principles in a convenient form, pre¬ 
pared from them three extracts, of varying strengths, in the 
following manner : the weakest of the three was made by 
thoroughly digesting thirty grains of the powdered Calabar 
bean in alcohol, carefully evaporating the strained fluid to 
dryness, and then adding to the residue one drachm of water. 
This formed a muddy solution, of a light, reddish-brown tint. 
In strength, one minim of this solution corresponded to about 
half a grain of the bean. The second extract was formed by 
evaporating a portion of the first to about a quarter of its 
volume; so that one minim of this extract corresponded to 
about two grains of the bean. The third extract was the 
strongest, and was prepared like the first, except that the 
proportions differed; so that one minim of it in strength 
corresponded to four grains of the bean. With these solu¬ 
tions I then proceeded to perform the following experiments, 
in which I had the able assistance of Dr. Grainger Stewart, 
with the intention of elucidating the exact effects the Calabar 
bean is capable of producing on the eye/^ 
Several experiments with this agent are then described, 
the details of which are too exclusively medical for our pages; 
but the following are the conclusions arrived at by the author: 
These experiments prove that the local application of the 
Calabar bean to the eye induces, first, a condition of short¬ 
sightedness. That this is present, and the cause of the in¬ 
distinctness of distant vision, cannot be doubted, as it is 
relieved by the use of concave glasses. The fact that objects 
appear larger and nearer than natural may be attributed to 
the induced myopia. And, second, it occasions contraction 
of the pupil, and, sympathetically, dilatation of the pupil of 
the other eye. We further observe, that atropine possesses 
the power of counteracting its effects, and, mce versdy that it 
is capable of overcoming the effects produced by atropine. 
The first symptom noticed is dimness of distant vision, and 
shortly after the pupil becomes contracted; the symptoms 
also subside in the same order,—first, the derangement of 
accommodation, and then the affection of the pupil.'’’’ 
