This product of the Niger and Old Calabar river was known to the natives as a poison long before Europeans thought to apply it to medicinal uses.

Its action is that of a powerful sedative to the spinal cord, allaying its excitability, paralysing voluntary muscles, and reducing the sensibility of the skin. It has been found to control the spasms of tetanus, and its active principle, eserin, is employed to contract the pupil of the eye in opposition to belladonna or atropine, when, as has already been pointed out (see Belladonna), it is desirable to keep the inflamed iris-from contact with parts to which it may adhere.

In cases of impaction of the bowel, it has the reputation of exciting peristaltic action and facilitating the removal of the offending matter more quickly than any other agent.