They are about twenty-two inches long, in order that they may be applied, if required, to the most backward of the grinders, and of such substance, as renders impossible any springy action which might cause the bite to be lost when the force was applied. As will be imagined, forceps of such dimensions are not to be used by the unassisted hand. The reader, by looking at the end of the handles, will observe that one is comparatively large: the smaller of the two contains within it a female screw, and the other is only a plain eye. To act on these, a cross handle or lever is added, and of this the following is an outline. [Illustration] This, as is shown in the wood-cut, consists of two pieces, the smaller of which works freely in a hole made for its reception, and being curved at one end, can be either extended in the manner represented above, or laid close to the lever in the way depicted in the next view of the instrument. It is what is technically called a "tommy," and its use is to gain dispatch and power in the employment of the forceps. The main part consists of a rod of steel, having in the centre a screw, which at the end towards the "tommy" exhibits an enlargement or shoulder. Such are the various parts, and when using them, the operator having fixed the claws of the forceps upon the tooth he wishes to extract, gives the forceps to an assistant, whom he orders to hold them firmly in their situation. He then takes the handle, and introducing it through the open eye with the "tommy" as rapidly as possible, winds it round until he feels the grasp is secure. Any amount of power can be thus obtained; for as the screw threads through one handle, the shoulder presses against the other, and thus forcing the claws together, fixes them upon the substance which may be placed between them. When this is done, the operator closes or folds up the free lever, and using both hands, has at his command a power which will not necessitate employment of his utmost strength. [Illustration]