The earliest traders of the Mediterranean lands practised barter, and in the Homeric poems we find cattle and bronze utensils frequently mentioned as standards of value. In the later part of the eighth century or the early part of the seventh, coinage originated in Asia Minor, the earliest coins being merely rough lumps of metal with striations on the reverse made by the roughened surface of a punch. In the process of manufacture a flat blank of metal was placed red hot on a die, a punch was then held upon the reverse of the blank, and struck with a hammer. As no “collar” was employed, the metal of course spread at the edges, making the coin only roughly circular. With the advance of art the coin types received the attention of the best artists and craftsmen, and in consequence the value of Greek coins, both as original works of art and as historical documents, cannot be exaggerated. Roman coins, while not often beautiful, are an important source of information relative to political and economic conditions. These facts may be noted with regard to the practical side of ancient coinage; Greek coins are not dated, they will not stack, and marks of value are more often absent than present. The earlier Roman coins resembled the Greek in these features, but, later, marks of value were added and the date indicated. [Illustration: FIG. 143. DIKAST’S TICKET] A number of small bronze instruments in Case 5 may have been part of a physician’s or pharmacist’s case. They include several probes, one being double (fig. 144), spatulae (fig. 145), spoon-probes, and two scalpels or bistouries. The spatulae were used for preparing and spreading ointments, and also by painters in mixing colors. The dikast’s ticket gives us a glimpse of Greek city life. It is the ticket of a juryman, Epikrates, entitling him to sit in the ninth court at Athens, of which there were ten in all, and to draw three obols a day, about ten cents, a “living wage,” however (fig. 143). The statuette of a negro boy in Case C in the Seventh Room is a reminder of the important part taken by slave labor in ancient times. This was much greater among the Romans than in Greece. Slaves were sometimes captives taken in war, or their descendants, but were more frequently acquired through trade. Their condition was much better in Greece than in Rome. On the grave stele of a young man in the Sculpture Gallery (No. 7) a little slave stands beside his master. [Illustration: FIG. 144. FORKED PROBE] [Illustration: FIG. 145. SPATULAE] These are, of course, domestic or personal servants, but slaves formed a large part of the laboring class in Greece, and the proportion was still greater in Rome in the later Republican period and under the Empire. They worked on the farms, in the factories, and, most dangerous occupation of all, in the mines and quarries, as well as in the workshops of skilled artisans and as clerks and copyists in private and public offices.