The _Acta Martyrum_--the official records of the sufferings, death, and deposition or burial of the martyrs, written out at the time by appointed officers of the church--bear frequent testimony to the widespread existence of this custom. Other Christian writings, in prose and in poetry, refer to it frequently. We find it prevailing at Rome and in all Italy, in Carthage, in Sebaste, in Nicomedia, in Gaul, and throughout the church. It was the universal custom. About the time when the body of St. Januarius was transported from the original tomb where it had been laid during the persecution, to the church of St. Januarius, _extra muros_, at Naples, similar translations of the bodies of martyrs took place elsewhere. St. Ambrose, the great Bishop of Milan, gives an account of such a ceremony for the martyrs St. Gervase and St. Protasius, and again for the martyrs St. Vitalis and St. Agricola. He mentions finding in the tombs, in both cases, the blood of the martyrs which had been gathered and placed there. St. Gaudentius, Bishop of Brixia, about the same time, mentions a similar fact. Some centuries later, the northern barbarians were making raids into Italy, and had repeatedly broken into and desecrated the sepulchres in the catacombs, either in mere wantonness or in search for the treasures which they thought might be hidden there. In order to save the venerated relics of the martyrs from such outrages, the popes opened the tombs of the martyrs in the portions of the catacombs then accessible--a great portion being already closed up, either by the falling in of the roof or by the act of the Christians centuries before--and transferred the remains to the churches within the city for greater safety. In opening the tombs, these vases were often found, and hundreds of them are now in the churches or in the sacred museums of Rome. Three centuries ago, Bosio, and after him Aringhi, Boldetti, Mamachi, and others, penetrated into the catacombs, searched them anew, and came upon some of those portions which had not been disturbed at the time of the general removal. In such portions not a few unopened and undisturbed tombs of martyrs were found. Within lay the remains of the body--bones and dust--with sometimes the rusted fragments of the instrument of death, and frequently the vial, or ampulla, of the martyr’s blood. During the last forty years, the work of investigating the catacombs, which had been intermitted, has been taken up afresh and prosecuted with earnestness and skill by F. Marchi, Cav. de Rossi, and other eminent archæologists. They still come occasionally across the tombs of martyrs, evidently untouched since the day of deposition, and within them, or in the mortar by the head, the vases of blood are still found. Where these vials are so placed in the mortar as to be visible and accessible from without, the thin glass has generally been broken. But the bottom still remains firmly set in the mortar, and contains 209