Surgeons NEEDLES are generally made crooked, and their points triangular; however, they are of different forms and sizes, and bear different names, according to the purposes they are used for.
The largest are needles for amputation; the next, needles for wounds; the finest, needles for futures. They have others, very short and flat, for tendons; others, still shorter, and the eye placed in the middle, for tying together of vessels, &c. Needles for couching cataracts are of various kinds; all of which have a small, broad, and sharp point or tongue, and some with a fulcus at the point. Surgeons have sometimes used two needles in this operation; one with a sharp point for perforating the coats of the eye, and another with a more obtuse point for depressing or couching the opaque crystalline lens; but care should be taken in the use of any of these, that they be first well polished with cloth or leather, before they are applied to the eye.
Mr Warner observes, that the blade of the couching needle should be at least a third part larger than those generally used upon this occasion, as great advantages will be found in the depressing of the cataract, by the increased breadth of the blade of that instrument. The handle, also, if made somewhat shorter than usual, will enable the operator to perform with greater steadiness than he can do with a larger handled instrument.
It is to be observed, that needles of silver pierce more easily in stitching arteries after an amputation, than those made of steel.