Finally in 1760, Levret perfected his instrument, and it is described by his pupil Stein. It is 16.4 inches long, the pelvic curve is 2.3 inches, the greatest width of the fenestra3 2.1 inches. The extremities nearly meet. The fenestra3 are prolonged to the lock, so that a filet may be passed. The lock is a key. (Fig. 36 and 37.) &tellies Forceps.—Two in number, a long and a short. " The short (Fig. 38) has no pelvic curve. It is 11.7 inches long, 4.7 for the handles, and 1.9 between the fenestraa, the extremities of which meet. The handles are of metal lined with wood. They have a sink lock. The long forceps, is 13.3 inches long, 5 inches of which is handle; it has a pelvic curve, 1.8 inches high." (Naegele and Grenser.) Classic Forceps.—French lbrceps.—Forceps of Dubois, Pajot, (Figs. 39, 40, 41.) This is simply Levret's, slightly modified. It is composed of two branches, each divided into blade, lock, handle. The instrument is of steel, light and solid. It is nickel-plated. The mean length is 17.5 inches, from the end of the fenestra3 to the lock 9.3 inches, from the lock to the end of the handles 8.1 inches. When the instrument is flat the fenestrated portion is 3.1 inches above the horizontal line. The greatest width between the blades is, at 1.5 inches from the extremity, 1.9 inches. The fenestra is 1.1 inches wide. The weight is about two pounds. The instrument has both a cephalic and a pelvic curve. In order that the pelvic curve may be exact, Tarnier says that the extremities of the fenes tile should be 3.4 inches above the horizontal line. The handle-ends have hooks, the one concave and sharp, and the other, curved nearly at right angles, is also sharp and may answer for a perforator.
The articulation is by a pivot lock.
Figs. 40 and 41 represent the jointed forceps of Pajot. This joint makes the long forceps more portable without taking away from its so lidity.
When the head is below the brim, Pajot uses a short forceps, which is only 12 in. long. (Fig. 44.) The branches disarticulate at their middle, to receive blades of larger size. (Figs. 42, 43.) The .Forceps of Brunninghausen has a lateral articular cleft, but the pivot lock is replaced by a flat projection, and the articulation is made firm by the pressure of the two hands.
Naegele's Forceps (Figs. 45, 46, 47) is simply Brunninghausen's modi fied. Its length is 15.8 inches, of which 6.8 inches is for the handles. When the instrument is closed, the blades are separated, above the lock, at an angle of 39 degrees. The superior extremities are. .42 of an inch apart. The greatest.width between the fenestrated portions is 2.6 inches. The length of the blades is 8.9 inches, the greatest width is 1.6 inches. They narrow down towards the lock. The handles are of metal lined with wood. The lock is like that of Brunninghausen's. The handles have lateral projections.
Simpson's Forceps is 14 inches long, according to.Tarnier; the length of the handle is 5 inches, that of the blade, from the lock to the carve, is 2.34 inches, the fenestra measures 6.24 inches, the greatest width is
.46 inches from the extremity, and measures 1.6 inches. When the for ceps is locked, the greatest width between the blades is 2.9 inches; the distance between the extremities is .97 inches. There is one special point in the construction: Immediately above the lock, the blades separate sharply, and then turn at about a right angle to proceed parallel up to the fenestrEe. The lock is like Smellie's. The handles are of metal covered with wood.
Stoltz's Forceps (Fig. 49) is thus described by Aubenas, the translator of Naegele and Grenser: " This forceps is not quite as long as the Parisian, and a little longer than the usual German forceps. It is 16.3 inches long, measuring 8.5 inches from the lock to the end of the fenestrfe, and from the lock to the end of the handles 7.8 inches. The blades are fenestrated for 5.9 inches. The greatest width of the fenestrEe is at the junction of the upper with the middle third, and is .078 of an inch. The greatest dis tance apart of the fenestrEe is at the upper third of the ellipsoid, and is 2.73 of an inch. The separation begins at 1.5 inches from the lock, and the curve begins at 3.9 inches from this point. At the extremity the blades are .39 of an inch apart. The blades are concave.
" It results from this disposition of the blades that they are longer than is customary; the fenestrae are wider open; the curve on the flat is more pronounced; the separation is greater than usual; the ellipsoid is near the extremities.
" The handles are of roughened wood, with two lateral wings, with arti culations, whereby they may open and shut.
" Such is the instrument which Prof. Stoltz has used for twenty-nine years, and which is praised by all who use it." l'relat's .Fbrceps (Fig. 50) is less massive and heavy than the ordinary.
It is 15.9 inches long, and the greatest width of the fenestra3 is 1.8 inches. The blades are rounded, and polished on both surfaces. The lock is Brunninghausen's. The handles have no hooks, and near the end are perforated for a steel rod, which aids in traction. This forceps is peculiar from the groat elasticity of its blades, and therefore they can adapt themselves to the foetal head with less risk of injury.
All the above forceps necessitate the introduction of the right blade first, else the blades will cross, and to obviate this the following forms have been devised.
Forceps of Thenance (Fig. 51); of Valette (Fig. 52); of Tarsitani (Fig. 53); of Antoine Petit (Fig. 54); of Baumers (Fig. 55); of Campbell (Fig. 56); of Mattel (Fig. 57.) Finally, we may mention the leniceps of Mallet: (Fig. 58), and the Iv trorep8 of Hamon (Fig. 59). The latter, in common with all others but the inventor, we reject absolutely. Its acceptance would, as Tarnier says, be going back two hundred years.