The earliest scarificators were simple square brass boxes, with cocking and release levers and 16 pointed blades. By 1780, illustrations in surgical works showed that the bottom of the scarificator was detachable. Thus, although the illustrations do not show the screw for regulating the height of the blade cover, provision may already have been made for adjusting the depth of cut of the blades.[116] Square or German-style scarificators continued to be sold in Germany throughout the nineteenth century. The earlier models (late eighteenth, early nineteenth century) were frequently embellished with ornate decoration, and had pointed blades. Some were quite tall. A specimen dated 1747, in the Wellcome Medical Museum collection, is 14.4 cm high and 4.5 cm wide at the base. (Figure 12.) [Illustration: FIGURE 12.--Lavishly decorated scarificator, 18th century. (Held by the Wellcome Institute of the History of Medicine, London. Photo courtesy of the Wellcome.)] The later models (mid- to late nineteenth century) were wider and plainer and had arched or crescent shaped blades (which made a cleaner lesion), but the internal mechanism remained the same. Square scarificators all had 16 steel blades that cut in the same direction and were arranged on three rods of five, six, and five blades respectively. At one end of each rod was a gear pinion. The cocking lever, protruding through an aperture at the top of the scarificator, broadened out into a flat plate with as many gear sectors as blade rods. The plate was held against the interior of the scarificator by a heavy support rod running the width of the scarificator, in such a way that the gear sectors of the cocking lever meshed with the pinions on the blade rods. Pulling up on the cocking lever turned the blades 180 degrees. A heavy flat cantilever spring, attached at one end to the bottom of the case, was caught under a protuberance on the cocking lever and bent as the cocking lever was pulled. As the blades were turned, a catch slipped over a tooth on the cocking lever, and held the blades in place. Nineteenth-century octagonal scarificators generally had two catches, the first exposing the blades, and the second rotating them a full 180 degrees. Pressure on the release lever pushed the catch off the tooth on the cocking lever, thereby releasing the lever and allowing the spring to snap the apparatus back to its original position. Releasing the spring brought the blades around so quickly that their movement could not be seen. (Figure 13.) [Illustration: FIGURE 13.--Interior of square scarificator. (NMHT 152130 [M-4771]; SI photo 76-9111.)]