SENNA Bombay or East Indian, from C. angustifolia of southern Arabia and various parts of India ; and the Tinnevelly, which is merely the last named species cultivated in India ; the leaves 6ENNAAR 769 Cassia acuti folia. Plant reduced ; leaf and pod of natural size. of this are much larger, as the plant is more luxuriant. The gathering of the first two is done mainly at the close of the rainy season, in September ; the bushes are cut and exposed to the sun until the leaves are quite dry, when they are separated by beating with sticks ; the whole and broken leaves, the small stems, and the pods are sent to the place of export. Some of it is garbled to remove extraneous matters before it is shipped. Tinnevelly senna, being a cultivated product, is collected with more care, and is a very superior variety of the American Senna (Cassia Marilandica). drug. Senna was formerly much more con- taminated by foreign leaves than now ; the poisonous coriaria myrtifolia of southern Eu- rope was used to adulterate it ; in Alexandria senna argel leaves may be often found, but as this (sarcostemma argel) grows with the senna plants, it is supposed to be an accidental ad- mixture. Senna is an active cathartic, and is largely used both by physicians and in domes- tic practice ; it is usually given in infusion, but sometimes in the fluid extract, tincture, and confection. It contains two bitter principles, and a cathartic acid upon which its activity chiefly depends. The active principle is read- ily changed by long continual heat and expo- sure to the air ; hence the infusion should al- ways be made in a covered vessel. American senna, or wild senna as it is sometimes called, is cassia Ma/rilandica, a perennial herbaceous plant, which grows from New England south- ward and westward; the root produces nu- merous erect stems 2 to 4 ft. high, clothed with leaves which have six to nine pairs of lance-oblong, obtuse leaflets, the common peti- ole bearing at its base a conspicuous club- shaped gland ; the bright yellow flowers are in axillary racemes, the two lower petals are the largest, and the anthers of the three upper stamens are deformed and imperfect ; the fruit is a narrow, somewhat curved, hairy pod, 3 to 4 in. long. This is a very showy plant, and is now and then seen in gardens, though it is not so well appreciated here as it is in Europe. The leaves are gathered for medicinal use ; they possess properties similar to those of the im- ported senna, but are less active, a third larger dose being required to produce the same effect. SEMAAR, a country of Africa, forming part of the territory commonly known as Nubia, and now included in the aggregation of Nile provinces constituting the dependency of Egypt officially known as Soodan. It is bounded E. by Abyssinia and W. by Kordofan, and ex- tends S. from the junction of the Blue and White Nile in lat. 15 36' N. to about lat. 10, but its boundaries are not well defined; area about 50,000 sq. m. ; pop. 1,500,000. It con- sists chiefly of the peninsular territory lying between the Bahr el-Azrek or Blue Nile on the east and the Bahr el-Abiad or White Nile on the west, with its N. extremity at Khar- toom. The chief towns are Khartoom, where the governor resides, Sennaar, the former cap- ital, on the Blue Nile, and Wat Medineh, de- scribed by Sir Samuel Baker as the principal trading place on the same river. The country consists of a plain from 1,400 to 1,500 ft. above the sea. There are some isolated summits nearly 1,000 ft. above the surrounding coun- try; and toward the S. boundary the surface becomes very mountainous. The plain of Sen- naar rests upon a regular horizontal stratum of sandstone, and the mountains consist of crys- talline rocks, clay slate, and limestone; while many of the isolated hills are composed of granite, and some contain veins of auriferous quartz and gneiss. Iron ore is abundant, and salt is found on the White Nile and at Khar- toom. The soil of the plain is for the most part a rich black mould, though there are many
