THE LEVER.
Variously modified, and used successively by Titsing, Rechberger, Cam per, Zeller, Bland, Boeckmann, Rigodeaux (Douai), Warocquier (Lille), it found in the forceps a formidable rival. Levret and Smellie were its first and most enthusiastic advocates. Baudelocque and his pupils rejected it, although the former had modified it advantageously by fenestrating the blade. (Fig. 119.) It was again advocated by Herbiniaux, Den man, Sims, Douglas, Nesbit, Cole, Griffith, Ford, Cooper and others, and rejected almost absolutely in Germany. It was modified further by V erardini (Bologne), (Fig. 120), Bodaert (Figs. 121 to 123,) and used by Coppel, Fraeys (Gand), Marchant of Charenton, Fabri (Bologne), Hubert, jr., who added to it three inches of blade, and two holes through which a cord was passed, (Fig. 124); and finally, of late years, it has been studied by Jacquemier and Tarnier. Nevertheless, the forceps is to-day universally admitted superior, and, as Jacquemier says: " The real ques tion to-day is, whether in contraction at the pelvic inlet, allowing of the passage of the head, but where the forceps is lacking in ease of applica tion and direction of traction, the lover is not a better instrument, a more powerful tractor, and less dangerous to mother and to child. Results from its use would seem to prove this. It ought only to act, as indeed it was alone devised, on the fetal occiput." According to Wasseige, the lever may act in three different ways: 1. Like a lever of the first class, the power of which is at the handle, the fulcrum towards the middle of the blade, under the symphysis, and the resistance at the foetal head. The power is to the resistance as P. R. to P.F.; and hence if Bodaert's lever is inserted three inches (Fig. 121), the force is tripled, the fulcrum is submitted to a pressure represented by the sum of the forces (power and resistance) applied to the two arms of the lever, supposing them parallel.
2. The instrument should be inserted so that the power is placed between the resistance and the fulcrum—that is to say, the handle is to be fixed at P, while the other hand pulls at F, in the direction of the arrow. (Fig. 122.) Then there is no pressure at the pubes; but in order to over come the resistance, a force superior to it must be used.
3. Finally traction may be made on the lever in the di rection of the two arrows (Fig. 123); we thus dimin ish pressure upon the pubes, and the resistance is more easily overcome.
Herbiniaux aimed at this mixed method when he passed a filet through the fenestra of his instrument, by pulling on the cords and lifting by little jerks.
Hilbert, the son, advises holding the handles of the instrument, and making traction only on the filet ends passed through the holes in the blade. (Fig. 124.) The direction given to the head varies necessarily with the inclination of the instrument to the fulcrum, and on the point of application to the head. Thus: 1. If the blade be inserted parallel to the symphysis, the head is pushed backward by pressure on the handle; and as this is lifted the head is finally pushed downward. 2. By lifting the handle, that por tion of the head on which the blade rests, may be rotated to right or to left, or flexed or extended. In other words, as Hubert, the younger, says, we can treat it as we do a billiard ball, by touching it where we please.
The method of using the lever is very much like that of the forceps. The blade may be placed at once where it should lie. Tarnier prefers to insert it behind near the sacro-sciatic ligament, and then to bring it forward spirally. Once well applied, it ought to lie next to the posterior surface of the pubes, its action on the head being from in front back wards. " When, says Tarnier, the lever is well applied, the handle is raised, and the instrument taking purchase at the symphysis acts like a first-class lever. The head is lowered by the power at the handle, and Continuing this motion with a few tractions, the head is delivered. To avoid contusion of the urethra, the lever should be wrapped with linen, or with rubber, and placed to one side of the median line. It easily slips when applied as above, and pressure on the ischio-pubic ramus contuses it; to prevent this, the handle is firmly grasped in the middle by the left hand, to prevent slipping, at the same time making pressure backwards to re-enforce the fulcrum and diminish the pressure on the symphysis." Struck by the facts cited by Bodaert, and by those of Fabri, and of his own experiments, made with the lever, Tarnier concludes that it cannot be compared with the forceps as a tractor, since it acts by compressing the head from before backwards. But although it cannot take the place of the forceps, it may, and it should be used in certain cases. He thinks that the action of the lever should be studied in: 1. Vertex presentations. 2. Face presentations. 3. Presentation of the breech, after the body has been delivered, and the head remains.