" The woman is placed in the usual position, held by assistants, and tractions need only be made on the cord which commands the loops, when the fenestne are brought together with a force proportionate to the trac tions, and the infant's head is firmly held. (Fig. 70.) "With one hand the tractions are regulated at will, according to the index of the dynamometer; the other hand guides the handles of the forceps as may be desired, up or down, to the right or to the left. The opera tion is simple, and the tractions, although mechanical, may be made in any direction as readily as in the purely manual operation." Lately Tarnier has devised a forceps which we will soon describe. The above method has, in Tarnier's hands, resulted in four dead infants and two mothers out of seven cases.
The movable rod of Pros and of Poullet is another valuable modification mechanical tractors, but is not sufficient to overcome our objections, or still the head must be seized either in the bi-temporal or bi-parietal dameter, and although this is possible in the excavation, it is nearly im )ssible at the superior strait, in particular when there is marked pelvic formity, and this is, above all, the case in which the advocates of mechanical tractors claim the greatest utility. Further, mechanical trac tors do not allow us to take cognizance of rotation movements. For these reasons, chiefly, we are in favor of relegating mechanical tractors to the armamentarium of the veterinary surgeon, never forgetting that the lives entrusted to our care are far more valuable than those of the cow and her calf, with both of whom we may, if we please, in full conscience, experi ment with any curious contrivance. With the mother and the child we are never so justified.
Brute force is not what the ace,oucheur aims at, but intelligent reason ing force; and although I may need only a force of 88 pounds with a mechanical tractor, I would far rather exert one of 135 with my hand, convinced, as I am, that thus there is less likelihood of injury than with 88 used blindly.
While now certain gentlemen have been trying to apply mechanical traction to labor, others have aimed at modifying the forceps so as to make it less dangerous to the perineum, and to allow of traction in the axes of the strait and of the excavation.
Hermann's 1844, Hermann, of Berne, had constructed a forceps, (Figs. 71, 72), which possessed not only a perineal curve, like that in the forceps of Mulder and of Johnson, but also a considerable pel vic curve, with long blades, and a special rod applicable either above or below the instrument, according to the high or the low situation of the head.
Ifuberea Forceps.—In 1860, Hubert de Louvain, struck by the fact that the shape of Levret's forceps prevented traction in the axis of the superior strait, without injury to the perineum, modified them by fixing between the handles a steel rod, directed backwards, and traction by which is possible in the desired direction. (Fig. 73.) Hartmann'a Ibrceps.—In 1870, Hartmann added to the forceps a rod like that of Hubert, but he placed it above the lock. (Fig. 74.) " If, he says, " the ordinary forceps is applied to the head at the brim, traction will not be made in the axis of the pelvis, but from above down wards, and particularly forwards, and the tendency of the head, hence, is to press against the anterior wall of the pelvis.
" When, however, the rod ad is applied, if the operator presses with his arm in the direction e to e, through the lock, the action on the fcetal head will be, at the same time, from i to i, and the resultant of the forces is the diagonal ft. But since the operator does not press perpendicularly, but obliquely, that is to say, from above backwards, below and in front, about in the direction from in to nn, the head is compressed from u to tz, and the resultant is consequently the diagonal fr. If, on the contrary, pressure be applied to the handle d of the rod ad, from in front back wards, the direction of the pressure becomes di, and the direction of the traction remaining fic, the diagonal of the forces if and r will become fk. If now we exaggerate pressure beyond traction, the diagonal will alter from k to k', and the head, as it descends, will do so in the axis of the pelvis, and will not press against the anterior pelvic wall." • Morales has also devised two forceps, which, although progressive mod ifications, are open to serious objections.
Finally, Tarnier, from 1877 to 1879, invented over thirty forceps, of which we will describe here only the first and the last model. (Figs. 75 and 76.) The following are the peculiarities of the first model, that of 1877. " It is composed of two handles, and of two traction rods. (Fig. 75.) The rods are inserted into a transverse bar at p, and are parallel as in the forceps of Thenance. The fenestrie are not as long as in the classic for
ceps; the instrument has a perineal curve, that of Morales modified; the traction rods and the handles are united by a freely movable articulation. To apply this forceps: Articulate each traction rod to its corresponding blade, and this is easily done. Holding both in the hand the fenestra is applied to the head in the usual fashion. When both blades have been introduced, the forceps is locked with the traction rods below. Com pression is applied to the head by means of a screw, working from one handle to the other. The traction rods are inserted into the transverse traction bar at p. During traction on this bar, the handles act as an in dex of the direction in which traction should be made, and the operator has only to follow the oscillations of these handles, keeping the traction rods about one-half an inch apart from the handles." (Aubenas.) According to Tarnier, the above instrument is preferable to the ordi nary: " 1. Traction need not be so energetic. The whole of the traction force is utilized. If the head resists with a force of 37 pounds, then only 17 pounds traction force need be exerted by the instrument, while with the ordinary forceps greater force would be requisite on account of the necessary decomposition of this force. 2. With this instrument all the utilized force acts on the head in the pelvic axis without any compression of the maternal parts. 3. Since traction is made in the pelvic axis, the head has no tendency to escape from the fenestne. 4. The traction handle being transverse, the grasp of the operator's hand is firmer. 5. Compression once made by the screw v, this is not increased during traction; while with the ordinary instrument, the hands of the operator make greater compression the greater the traction, and the antero-posterior diameter of the head is thus elongated, and the obstacles to labor increased when the pelvis is narrowed in its antero-posterior diameter. 6. The fenestne being short, we may always make traction in the pelvic axis without fear of tearing the posterior commissure. 7. Not only may axis-traction be made, but the head is at liberty to follow the vaginal curve. Owing, further, to the movable point at the articulation of the traction rods and the handles, the head may spontaneously execute its rotatory mevement around the pelvic axis. When, however, it is desired to make this rotation artifi cially, then care must be taken to seize the rods and the handles together, for if the endeavor is made to rotate the head by means of the rods alone, they might be broken. 8. Finally the new instrument has an indicator needle, wherein it is peculiar over all other forceps." • While Tarnier's pupils accepted this instrument with the greatest en thusiasm, far otherwise was it with Stoltz, Depaul, and, above all, Pajot. The latter, in his discussion with Tarnicr, thus compares the classic and the new instrument: " Tarnier's Forceps: A complicated instrument, deprived of all lever property, less easy to introduce and to manage, only able to do what all other forceps may. 2. An instrument still unproved, of value where the head is movable above the superior strait. 3. An in strument with an indicator needle, of no use when the operator knows his business. 4. Fenestne useful in cases where delivery may be accom plished with dressing-forceps, but useless otherwise on account of their small size. 5. An instrument said to be of value because by it traction may be made in the pelvic axis, a superfluous advantage in 90 cases out of 100, and still to be proved true in the remaining 10. Classical lbr ceps: 1. An instrument, simple, handy, easy of introduction and of man agement, with two branches instead of four, without screw, successful in innumerable cases, according to need, tractor, lever, compressor, accord ing to exercised traction, less likely, hence, to slip in difficult cases, and when it does slip, at once notifying the operator. 2. An instrument giv ing full scope to the head between the tractions, and more than Tarnier's instrument during the tractions, the head never being elongated antero posteriorly more than a firm hold necessitates. 3. The masters in the art consider the principle even of Tarnier's instrument superfluous." The last model of Tarnier's instrument differs markedly from the first, for the perineal curve no longer exists, and the fenestrre are similar to those in the classic forceps. It is, in brief, the classic forceps to which traction rods are attached. (Figs. 76, 77, 78, 79.) The following is the description of the instrument: It is 16 inches long. When lying fiat, the end of the blades projects 3.12 inches above the plane.