Readers of St. Jerome's works are familiar with the fact that he often quotes Greek and Hebrew words in the course of these, sometimes depending on his master Origen, sometimes depending on his personal knowledge of both languages, which was considerable. In the autographs of these works it was his custom to place a line over the top of such words, as a sign that they were foreign. Really old manuscripts of Jerome's works, apart from Vulgate MSS., are now rare. Such as were known to Traube are listed in his Hieronymi Chronicorum codicis Floriacensis fragmenta Leidensia, Parisina, Vaticana phototypice edita (Lugd. Bat.1902). But good early minuscule MSS. of his works in many cases preserve these horizontal lines, and record the Greek and Hebrew words with considerable accuracy. As time goes on, the lines tend to disappear, and Latin transliterations, with or without the Greek, become more and more common. Most of the editions of Jerome are defective in two respects among others: they were not based on the oldest and best manuscripts, and the editors did not know very much Greek. It is hoped that the details furnished below will have some interest for students of Greek writing in the latter part of the fourth century.