The Tiber is now but a narrow stream in the midst of its ancient bed. The Romans had never embanked the swift-flowing river, and the enormous deposits of the yellow sand which give it its traditional colour, and which threaten to completely dam the river by the island of the Tiber, may afford the explanation. The inundations of 1900 in fact reached the same level as those of 1872, as we may see recorded in the neighbouring church of Santa Maria in Cosmedin. Few spots in Rome exceed in varied interest the _isola sacra_ which with its two historic bridges the _pons Fabricius_ and the _pons Cestius_ spans the Tiber at the heart of the city. Here was the temple to Aesculapius, whose worship had been introduced into Rome during a time of pestilence in obedience to the Sibylline oracles. The island itself thereafter assumed the form of a huge stone ship, faced with travertine, the prow with the sculptured staff and serpent of the god being still clearly visible; and here Greece and Rome met a civilisation and an art still older than their own, for the mast of this great ship is formed by an Egyptian obelisk. Hard by is the district where the Romans, who had borrowed from them their gods and their cult, compelled the "_turba impia_" ("the impious crowd") of Etruscans to dwell; while the walled enclosure in which, from the eleventh century onwards, Christian Rome obliged the Jews to live, is approached by the Fabrician bridge, as we may gather from the inscription in Hebrew and Latin on the little church of San Giovanni Calibita, beneath a painting of the Crucifixion, which says: "I have spread forth my hands all the day to an unbelieving people, who walk in a way that is not good." In the early twelfth century Otho III. brought, as he believed, the body of the Hebrew apostle Saint Bartholomew to this island, as 1400 years earlier the cult of Aesculapius had been brought there from Greece. The city of Beneventum had, however, it is supposed, palmed off on the emperor the body of Saint Paulinus of Nola which rests in the church dedicated to the apostle by the side of that of Saint Adelbert the apostle of the Slavs. The Franciscans came to the _isola sacra_ in the sixteenth century, and one of the friars of Saint Bartholomew's is the popular dentist of the poor from all quarters.