In addition to horn cups, the ancients employed bronze cups in which a vacuum was obtained by inserting a piece of burning flax or linen into the cup before its application to the skin. Most Greek and Roman cups were made of metal.[95] Although Galen already preferred glass cups to metal cups for the simple reason that one could see how much blood was being evacuated, metal cups were used until modern times. Their main virtue was that they did not break and thus could be easily transported. For this reason, metal cups were especially useful to military surgeons. Brass and pewter cups were common in the eighteenth century, and tin cups were sold in the late nineteenth century. Since the latter part of antiquity, cups have been made of glass. The Smithsonian possesses two Persian opaque glass cups dating from the twelfth century, called "spouted glasses" because of the spout protruding from the side of the cup by which the cupper exhausted the air with his mouth. Similar spouted glasses were illustrated by Prosper Alpinus (sixteenth century), so designed that the blood would collect in a reservoir instead of being sucked into the cupper's mouth. Like the horn cups illustrated by Alpinus, the glass cups were provided with a small valve made of animal skin. It appears that the sixteenth-century Egyptians were not familiar with the use of fire for exhausting cups. (Figure 9.) Cupping and leeching were less frequently practiced in the medieval period, although general bloodletting retained its popularity.[96] When the eastern practice of public steam baths was reintroduced into the West in the late sixteenth and early seventeenth centuries, cupping tended to be left in the hands of bath attendants (Bagnio men) and ignored by regular surgeons. Some surgeons, such as Pierre Dionis, who gave a course of surgery in Paris in the early eighteenth century, saw little value in the operation. He felt that the ancients had greatly exaggerated the virtues of the remedy.[97] Another French surgeon, Rene de Garengeot, argued in 1725 that those who resorted to such outdated remedies as cupping had studied the philosophical systems of the ancients more than they had practiced medicine. He accused the admirers of the ancients of wishing to kill patients "with the pompous apparatus of wet cupping."[98] (Figure 10.) [Illustration: FIGURE 9.--Persian spouted cupping glass, 12th century. (NMHT 224478 [M-8037]; SI photo 73-4215.)]