CALABAR (or Old Calabar), a seaport of West Africa in the British protectorate of Southern Nigeria, on the left bank of the Calabar river in 4° 56′ N., 8° 18′ E., 5 m. above the point where the river falls into the Calabar estuary of the Gulf of Guinea. Pop. about 15,000. It is the capital of the eastern province of the protectorate, and is in regular steamship and telegraphic communication with Europe. From the beach, where are the business houses and customs office, rise cliffs of moderate elevation, and on the sides or summits of the hills are the principal buildings, such as Government House, the European hospital and the church of the Presbyterian mission. The valley between the hills is occupied by the native quarter, called Duke Town. Here are several fine houses in bungalow style, the residences of the chiefs or wealthy natives. Along the river front runs a tramway connecting Duke Town with Queen Beach, which is higher up and provided with excellent quay accommodation. Among the public institutions are government botanical gardens, primary schools and a high school. Palms, mangos and other trees grow luxuriantly in the gardens and open spaces, and give the town a picturesque setting. The trade is very largely centred in the export of palm oil and palm kernels and the import of cotton goods and spirits, mostly gin. (See Nigeria for trade returns.)
Calabar was the name given by the Portuguese discoverers of the 15th century to the tribes on this part of the Guinea coast at the time of their arrival, when as yet the present inhabitants were unknown in the district. It was not till the early part of the 18th century that the Efik, owing to civil war with their kindred and the Ibibio, migrated from the neighbourhood of the Niger to the shores of the river Calabar, and established themselves at Ikoritungko or Creek Town, a spot 4 m. higher up the river. To get a better share in the European trade at the mouth of the river a body of colonists migrated further down and built Obutöng or Old Town, and shortly afterwards a rival colony established itself at Aqua Akpa or Duke Town, which thus formed the nucleus of the existing town. The native inhabitants are still mainly Efik. They are pure negroes. They have been for several generations the middle men between the white traders on the coast and the inland tribes of the Cross river and Calabar district. Christian missions have been at work among the Efiks since the middle of the 19th century. Many of the natives are well educated, profess Christianity and dress in European fashion. A powerful bond of union among the Efik, and one that gives them considerable influence over other tribes, is the secret society known as the Egbo (q.v.). The chiefs of Duke Town and other places in the neighbourhood placed themselves in 1884 under British protection. From that date until 1906 Calabar was the headquarters of the European administration in the Niger delta. In 1906 the seat of government was removed to Lagos.
Until 1904 Calabar was generally, and officially, known as Old Calabar, to distinguish it from New Calabar, the name of a river and port about 100 m. to the east. Since the date mentioned the official style is Calabar simply. Calabar estuary is mainly formed by the Cross river (q.v.), but receives also the waters of the Calabar and other streams. The Rio del Rey creek at the eastern end of the estuary marks the boundary between (British) Nigeria and (German) Cameroon. The estuary is 10 to 12 m. broad at its mouth and maintains the same breadth for about 30 m.
CALABAR BEAN, the seed of a leguminous plant, Physostigma venenosum, a native of tropical Africa. It derives its scientific name from a curious beak-like appendage at the end of the stigma, in the centre of the flower; this appendage though solid was supposed to be hollow (hence the name from φῦσα, a bladder, and stigma). The plant has a climbing habit like the scarlet runner, and attains a height of about 50 ft. with a stem an inch or two in thickness. The seed pods, which contain two or three seeds or beans, are 6 or 7 in. in length; and the beans are about the size of an ordinary horse bean but much thicker, with a deep chocolate-brown colour. They constitute the E-ser-e or ordeal beans of the negroes of Old Calabar, being administered to persons accused of witchcraft or other crimes. In cases where the poisonous material did its deadly work, it was held at once to indicate and rightly to punish guilt; but when it was rejected by the stomach of the accused, innocence was held to be satisfactorily established. A form of duelling with the seeds is also known among the natives, in which the two opponents divide a bean, each eating one-half; that quantity has been known to kill both adversaries. Although thus highly poisonous, the bean has nothing in external aspect, taste or smell to distinguish it from any harmless leguminous seed, and very disastrous effects have resulted from its being incautiously left in the way of children. The beans were first introduced into England in the year 1840; but the plant was not accurately described till 1861, and its physiological effects were investigated in 1863 by Sir Thomas R. Fraser.
The bean usually contains a little more than 1% of alkaloids. Of these two have been identified, one called calabarine, and the other, now a highly important drug, known as physostigmine—or occasionally as eserine. The British pharmacopoeia contains an alcoholic extract of the bean, intended for internal administration; but the alkaloid is now always employed. This is used as the sulphate, which has the empirical formula of (C15H21N3O2)2, H2SO4, plus an unknown number of molecules of water. It occurs in small yellowish crystals, which are turned red by exposure to light or air. They are readily soluble in water or alcohol and possess a bitter taste. The dose is 160-130 grain, and should invariably be administered by hypodermic injection. For the use of the oculist, who constantly employs this drug, it is also prepared in lamellae for insertion within the conjunctival sac. Each of these contains one-thousandth part of a grain of physostigmine sulphate, a quantity which is perfectly efficient.
Physostigmine has no action on the unbroken skin. When swallowed it rapidly causes a great increase in the salivary secretion, being one of the most powerful sialogogues known. It has been shown that the action is due to a direct influence on the secreting gland-cells themselves. After a few minutes the salivation is arrested owing to the constricting influence of the drug upon the blood-vessels that supply the glands. There is also felt a sense of constriction in the pharynx, due to the action of the drug on its muscular fibres. A similar stimulation of the non-striped muscle in the alimentary canal results in violent vomiting and purging, if a large dose has been taken. Physostigmine, indeed, stimulates nearly all the non-striped muscles in the body, and this action upon the muscular coats of the arteries, and especially of the arterioles, causes a great rise in blood-pressure shortly after its absorption, which is very rapid. The terminals of the vagus nerve are also stimulated, causing the heart to beat more slowly. Later in its action, the drug depresses the intra-cardiac motor ganglia, causing prolongation of diastole and finally arrest of the heart in dilatation. A large lethal dose kills by this action, but the minimum lethal dose by its combined action on the respiration and the heart. The respiration is at first accelerated by a dose of physostigmine, but is afterwards slowed and ultimately arrested. The initial hastening is due to a stimulation of the vagus terminals in the lung, as it does not occur if these nerves are previously divided. The final arrest is due to paralysis of the respiratory centre in the medulla oblongata, hastened by a quasi-asthmatic contraction of the non-striped muscular tissue in the bronchial tubes, and by a “water-logging” of the lungs due to an increase in the amount of bronchial secretion. It may here be stated that the non-striped muscular tissue of the bladder, the uterus and the spleen is also stimulated, as well as that of the iris (see below). It is only in very large doses that the voluntary muscles are poisoned, there being induced in them a tremor which may simulate ordinary convulsions. The action is a direct one upon the muscular tissue (cf. the case of the gland-cells), since it occurs in an animal whose motor nerves have been paralysed by curare.
Consciousness is entirely unaffected by physostigmine, there being apparently no action on any part of the brain above the medulla oblongata. But the influence of the alkaloid upon the
