732 Y A R Y A W History. As earl} 7 as the 9tli century the Slavonians had become masters of the Yarostavl territory, which was formerly occupied by the Finnish stems Vess and Merya, as also by Mordvinians, Muroms, and Tcherernisses in the south. Rostoff was already in existence ; but Yaroslavl, Rybinsk, and Uglitch begin to be mentioned in the annals only in the llth and 12th centuries. The independent prin cipality of Rostoff was divided in the 13th century into three parts, but these were soon afterwards successively annexed to Moscow. See the Trudy of the Yaroslavl Statistical Committee, 8 vols., and the Vyestnik of the Yaroslavl zemstvo, published since 1872. (P. A. K.) YAROSLAVL, capital of the above government, stands on the right bank of the Volga, at its junction with the Kotorost, 173 miles by rail to the north-east of Moscow, and had a population of 48,310 inhabitants in 1884 ; but this number is temporarily much increased during the period of navigation. The suburbs of the town occupy the left bank and are inundated at high water. A fine quay borders the Volga for nearly two miles. The cathedrals and several churches are very old. The Uspenskiy cathe dral was begun in 1215 and rebuilt in 1648 ; the churches of the Preobrazhenskiy monastery, St John s, and Voskre- seniye date from the 15th and 17th centuries, the second being a fine specimen of the architectural style exemplified in the Vasiliy Blazhennyi church of Moscow. Yarostavl has a lyceum, founded by Demidoff, with a juridical faculty, three gymnasia (409 boys, 669 girls), and various primary schools. The manufactories, whose total production in 1862 barely reached the value of 200,000, now employ 5100 hands and yield an output valued at about 1,000,000 (one-half from one cotton-mill). The trade, especially that in corn, is very active and accounts for one-quarter of the whole traffic of the government. The Yarostavl merchants also carry on a large import trade in manufactured goods and groceries. The town of Yarostavl was founded in 1026-1036 by Yarosiav Yladimirovitch, who caused a wooden fort to be erected at the con fluence of the Kotorost with the Volga. It became the chief town of a principality in 1218 and remained so until 1471, when it fell under the dominion of Moscow. Even in the 13th century Yarostavl was an important town, and, although it suffered during subsequent wars, it maintained its importance until the 19th century, when the trade on the Volga and its rising manufactures again gave it a position of predominance in the upper basin of the Volga. YARRELL, WILLIAM (1784-1856), one of the most popular of British naturalists, was born at Westminster in June 1784. His father was a newspaper agent, and he himself succeeded to the business on his father s death, and prosecuted it till within a few years of his own. He availed himself of any interval of relaxation to enjoy such sport as the neighbourhood of London afforded, acquired the reputation of being the best shot and the first angler in the metropolis, and soon also became an expert natural ist. In 1824 he became a fellow of the Linnean Society, and was a diligent contributor to their Transactions ; and he was one of the earliest members of the Zoological Society. The greater part of his leisure towards the end of his life was devoted to his two great works, The History of British Fishes (2 vols., 1836) and The History of British Birds (2 vols., 1843). These works are compiled on the same plan ; they contain accurate figures, with accompany ing descriptions, of every British fish or bird ; and they have from the first taken their position as standard authorities. Few books on natural history are more agreeable to the general reader : the style is pleasant, and the truth with which he describes the habits of the birds is such as might have been expected from a keen and ob servant sportsman. In 1856 he had an attack of paralysis, of which he died at Yarmouth on 1st September of the same year. YAWS is the name in use in the British West Indies and on the West Coast of Africa for a peculiar disease of the skin in Negroes. The learned name, first applied by Sauvages (1761), is frambcesia, from the likeness of the typical excrescences to a raspberry. For many years yaws was thought to be peculiar to the African Negro, either in his home (both west and east coasts) or in the West Indies and Brazil. But a disease the same in every respect has long been known in the East Indies (first mentioned by Bontius early in the 17th century), affecting the Malays rather than the Negroes, its chief seats being Amboyna, Ternate, Timor, Celebes, Java, and Sumatra. It has been identified more recently by De Rochas and other observers in New Caledonia and Fiji. The parangi of Ceylon has been shown by Kynsey to be the same as the West Indian yaws. Also in the Samoa group, to which there has been no Negro migration, an identical malady occurs. The closely allied verrugas of the Peruvian Andes (see WART) is so different in its endemic circumstances that it is not usually classified as a form of yaws. The account that follows applies equally to all of the local forms, while it has more especial reference to yaws in the Negroes of the West Indies. The general course of the disease is as follows. Previous to the eruption there may or may not be any disorder of health ; in child ren (who form a large part of the subjects of yaws) there will prob ably be rheumatic pains in the limbs and joints, with languor, debility, and upset of the digestion ; in adults of ordinary vigour the eruption is often the first sign, and it is attended with few or no constitutional troubles. The eruption begins as small pimples like a pin s head, smooth and nearly level with the surface ; they have a little whitish speck on their tops, grow rapidly, and reach the size of a sixpence or a shilling. The pustules then break, and a thick viscid ichor exudes and dries npon them as a whitish slough, and around their base as a yellowish brown crust. Beneath the whitish slough is the raspberry excrescence or yaw proper, a reddish fungous growth with a nodular surface. The favourite seats of the eruption are the forehead, face, neck, armpits, groin, genitals, perinaeum, and buttocks. Hairs at the seat of a yaw turn white. In young children or infants the corners of the mouth ulcerate, as in syphilis, and the perineal excrescences resemble condylomata. The pustules and excrescences do not all arise in one crop : some are found mature while others are only starting. If the patient be of sound constitution and good reaction, the yaws may reach the full size of a mulberry in a month, in which case they will probably be few ; but in persons of poor health they may take three months to attain the size of a wood-strawberry, in which case they will be numerous inversely to their size. Often there is one yaw much larger than the rest, and longer in falling ; it is called the "master yaw " or " mother yaw." On the soles of the feet (less often on the palms of the hands) the bursting yaws are as if im prisoned beneath the horny cuticle ; they cause swelling and tender ness of the foot, until set free by paring the callous skin down to the quick ; these yaws are called " crab yaws " or tubbas. Usually a yaw is painless unless when rubbed or irritated. The absence of pain is used as a diagnostic sign if there be any doubt as to the nature of the attack : a pustule is opened, and a little of the juice of capsicum dropped into it ; if it be a yaw, no smarting will be felt. In some cases a few yaws will show themselves long after the primary attack is over ; these are called "memba yaws" (from "re member "), the term being sometimes applied also to protracted cases with successive crops of eruption. Six weeks is the average time in a good case, from the first of the eruption to the fall of the excres cences ; in such regular cases a scar remains, it may be for many months, darker than the rest of the (Negro) skin. But the disease is often a much more tedious affair, the more protracted type having become common in the West Indies of recent years. In such cases the eruption comes out by degrees and as if with difficulty, crop after crop ; foul, excavating, and corroding ulcers may remain, or a limb may be in part seamed and mutilated by the scars of old ulceration. The scars after ulceration are not so dark as the skin around. That yaws is a communicable disease is beyond question ; but that it has always arisen by conveyance of yawey matter from a previous case is neither proved nor probable. Being to a great extent a disease of childhood, it is not usually conveyed after the manner of syphilis, but by contact in other ways (as in the epidemic syphilis of 1494-1520 and in recent circumscribed epidemics). An abrasion or wound of the surface, such as a chigoe bite or a cut of the foot, rs a likely point of entrance for the virus. If the yawey matter finds access to a pre-existing sore or ulcer, it causes the latter to take on a foul and sloughing condition. No sore or yaw is induced at the point of infection, which will probably be healed long before the eruption appears. It is said, however, that the pustules appear earliest and in greatest numbers on the skin near
the spot where the virus entered. They follow the infection at an