“First, when you introduce the instrument you are never sure of being in the uterus, but, when, besides the precaution I have above recommended, you feel that the axis of the instrument, or the extremity of the branches, is in a kind of vacuum. This sign would I own be a very equivocal one, for a person that should use this forceps without having practised surgery[[39]]; but so it will not be for him, whose sense of the touch is habituated to the feeling of instruments of different sorts, as they enter into empty cavities of vessels or of hollow organs, or in short of any cavity.
“Secondly, when by drawing towards yourself the instrument, you are assured of the preceding sign, you will feel a small resistence to a certain degree.
“Thirdly, the blades of the instrument should suffer themselves to be opened out with some sort of ease, and what is opened out should not make resistence enough for the blades to return with any violence to the place whence the opening out began.
“Fourthly, the blades in the instrument should, as they open wider and wider, rather tend to augment the diameter of the void of the instrument than diminish it.
“Fifthly, these same blades should, in their expansion, go a little depth in the vagina.
“If the man-midwife, (says Levret) perceive, that any of these favorable signs should be wanting, he ought to mistrust the success, and to have recourse to his sagacity for the remedying it.”
Thus far as to the handling this forceps of Levret’s, to whom the defectiveness of the English and French forceps had inspired an idea of providing such a supplement to it, from the richness of his own invention.
I do not wonder however at no instrument pleasing Mr. Levret so well as his own. Nothing is more common among the instrumentarians, than their disagreement about the make of their instruments. Some will have their forceps long, others short, some strait and flat, others curve: in short, there is no adapting the mechanism of it to their various fancies, so apt too as they are to change. Levret complains bitterly of the inability or injustice of the instrument-makers; but by what I believe of them, very unjustly. The gift of the fault is not in the instrument; it is in the use to which they are so often put of attempting impossibilities.
But now let us examine, what surely very competent judges have thought of this famous new forceps of Mr. Levret, which he calls his instrument.
When the book and instrument were presented the Royal Society at London, it appears by a quotation inserted by Mr. Levret himself, that his instrument was allowed to be ingenious enough, but that “there was nothing extraordinary in it.”