and strong solutions painted round the base of a boil at the beginning will abort its formation. Internally the nitrate has been used in the treatment of gastric ulcer, in ulcerative conditions of the intestine and in chronic dysentery. For the intestinal conditions it must either be given in a keratin-coated pill or injected high up into the rectum The oxide has been given in epilepsy and chorea. Nitrate of silver is eliminated from the system very slowly and the objection to its employment continuously as a drug is that it is deposited in the tissues causing argyria, chronic silver poisoning, of which the most prominent symptom is dark slate-blue colour of the lips, cheeks, gums and later of the skin.
Taken in large doses nitrate of silver is a powerful poison, causing violent abdominal pain, vomiting and diarrhoea with the development of gastro-enteritis. In some cases nervous symptoms and delirium supervene. The treatment consists in the use of solutions of common salt, followed by copious draughts of milk or white of egg and water or soap in water, in order to dilute the poison and protectthe mucous membranes of the oesophagus and stomach from its action.
SILVERFISH, a small active insect, so-called from the silvery glitter of the scales covering the body. It is less than half an inch long and is found in damp corners or amongst books and papers in houses. Although accredited with destroying paper and linen, it probably feeds only on farinaceous or saccharine substances. Scientifically it is known as Lepisma saccharina and belongs to the sub-order Thysanura of the order Aptera.
SILVERIUS, pope from June 536 to March 537, successor of Pope Agapetus I., was a legitimate son of Pope Hormisdas, born before his father entered the priesthood. He was consecrated on the 8th of June 536, having purchased his elevation from the Gothic king Theodotus. Six months afterwards (Dec. 9) he was one of those who admitted Belisarius into the city. He opposed the restoration of the patriarch Anthimus, whom Agapetus had deposed, and thus brought upon himself the hatred of Theodora, who desired to see Vigilius made pope. He was deposed accordingly by Belisarius in March 537 on a charge of treasonable correspondence with the Goths, and degraded to the rank of monk. He went to Constantinople, and Justinian, who entertained his complaint, sent him back to Rome, but Vigilius was ultimately able to banish his rival to Pandataria, where the rest of his life was spent in obscurity. The date of his death is unknown.
SILVES, a city of S. Portugal, in the district of Faro (formerly the province of Algarve); on the right bank of the river Silves at the head of its estuary, and 30 m. W.N.W. of Faro. Pop. (1900) 9687. Silves is surrounded by Moorish walls and dominated by a Moorish castle. It has a fine Gothic church. It has manufactures of corks and soap; and exports corn, vegetables and fruits. Large numbers of pigs are bred, and fishing is carried on in the river and at sea. Alphonso III. (1210-1248) wrested Silves from the Moors.
SILVESTER, the name of three popes.
Silvester I., bishop of Rome from January 314 to December 335, succeeded Melchiades and was followed by Marcus. The accounts of his papacy preserved in the Liber pontificalis are little else than a record of the gifts said to have been conferred on the Roman church by Constantine the Great. He was represented at the council of Nice. The story of his having baptized Constantine is pure fiction, as almost contemporary evidence shows the emperor to have received this rite near Nicomedia at the hands of Eusebius, bishop of that city. According to Döllinger, the entire legend, with all its details of the leprosy and the proposed bath of blood, cannot have been composed later than the close of the 5th century (cf. Duchesne, the Liber pontificalis, i. 109). The so-called Donation of Constantine was long ago shown to be spurious, but the document is of very considerable antiquity and, in Döllinger's opinion, was forged in Rome between 752 and 777. It was certainly known to Pope Adrian in 778, and was inserted in the false decretals towards the middle of the next century.
Silvester II., pope from 999 till 1003, and previously famous, under his Christian name of Gerbert, first as a teacher and afterwards as archbishop successively of Reims and Ravenna, was an Aquitanian by birth, and was educated at the abbey of St Gerold in Aurillac. Here he seems to have had Gerald for his abbot and Raymond for his instructor, both of whom were among the most trusted correspondents of his later life. From Aurillac, while yet a young man (adolescens), he was taken to the Spanish march by “Borrell, duke of Hither Spain,” prosecuting his studies. Borrell entrusted him to the care of a Bishop Hatto, under whose instruction Gerbert made great progress in mathematics. In this duke we may certainly recognize Borel, who, according to the Spanish chroniclers, was count of Barcelona from 967 to 993, while the bishop may probably be identified with Hatto, bishop of Vich or Ausona from about 960 to 971 or 972. In company with his two patrons Gerbert visited Rome, where the pope, hearing of his proficiency in music and astronomy, induced him to remain in Italy, and introduced him to the emperor Otto I. A papal diploma, still extant, shows that Count Borel and Bishop Octo or Otho of Ausona were at Rome in January 971, and, as all the other indications point to a corresponding year, enables us to fix the chronology of Gerbert's later life.
When brought before the emperor, Gerbert admitted his skill in all branches of the quadrivium, but lamented his comparative ignorance of logic. Eager to supply this deficiency he followed Lothair's ambassador Germanus, archdeacon of Reims, to that city, for the sake of studying under so famous a dialectician in the episcopal schools which were rising into reputation under Archbishop Adalbero (969-989). So promising a scholar soon attracted the attention of Adalbero himself, and Gerbert was speedily invited to exchange his position of learner for that of teacher. At Reims he seems to have studied and lectured for many years, having amongst his pupils Hugh Capet's son Robert, afterwards king of France, and Richer, to whose history we owe almost every detail of his master's early life. According to this writer Gerbert's fame began to spread over Gaul, Germany and Italy, till it roused the envy of Otric of Saxony, in whom we may recognize Octricus of Magdeburg, the favourite scholar of Otto I., and, in earlier days, the instructor of St Adalbert, the apostle of the Bohemians. Otric, suspecting that Gerbert erred in his classification of the sciences, sent one of his own pupils to Reims to take notes of his lectures, and, finding his suspicions correct, accused him of his error before Otto II. The emperor, to whom Gerbert was well known, appointed a time for the two philosophers to argue before him; and Richer has left a long account of this dialectical tournament at Ravenna, which lasted out a whole day and was only terminated at the imperial bidding. The date of this controversy seems to have been about Christmas 980, and it was probably followed by Otric's death, on the 1st of October 981.
It must have been about this time that Gerbert received the great abbey of Bobbio from the emperor. That it was Otto II., and not, as formerly supposed, Otto I., who gave him this benefice, seems evident from a diploma quoted by Mabillon (Annales, iv. 121). Richer, however, makes no mention of this event; and it is only from allusions in Gerbert's letters that we learn how the new abbot's attempts to enforce his dues waked a spirit of discontent which at last drove him in November 983 to take refuge with his old patron Adalbero. It was to no purpose that he appealed to the emperor and empress for restitution or redress; and it was perhaps the hope of extorting his reappointment to Bobbio, as a reward for his services to the imperial cause, that changed the studious scholar of Reims into the wily secretary of Adalbero. Otto II. died in December 983, leaving the empire to his infant heir Otto III. Lothair, king of the west Franks, claimed the guardianship, and attempted to make use of his position to serve his own purposes in Lorraine, which would in all probability have been lost to the empire but for the efforts of Adalbero and Gerbert. Gerbert's policy is to be identified with that of his metropolitan, and was strongly influenced by gratitude for the benefits that he had received from the first two Ottos.
According to M. Olleris's arrangement of the letters, Gerbert was at Mantua and Rome in 985. Then followed the death of Lothair (2nd of March 986) and of Louis V., the last Carolingian king, in May 987. Later on in the same year Adalbero crowned