It is true that many other and more or less complicated instruments have been devised for the purpose of facilitating the operation; and other methods, aside from that of the knife, have come of recent years into vogue; but, still, simplest means, as above given, have in the experience of most surgeons been proven to be the best. This statement, undeniably true for all surgical measures, is especially so for the operation under consideration, which is often necessarily undertaken without opportunity for elaborate preparation and under the most adverse and inconvenient circumstances. The more familiar, therefore, the surgeon is with his instruments, the better and more certain will be his work. Holding this view, it is unnecessary for me to more than briefly mention such instrumental aids as the grooved tenaculum of Chassaignac, the groove serving to guide the operator's knife into the trachea; the sharp double hooks of Langenbeck, which, after being caught in the tracheal walls to either side of the site of the intended incision, are sprung apart after the latter is made, thus dilating the wound and rendering the introduction of the tube easy; the tracheotome of Thompson, a pair of curved cutting forceps, the blades of which are caused to open by a screw after they have been plunged through the tracheal walls; that of Garin, a forceps with curved blades--one, the longest and sharpest-pointed, being made to penetrate the trachea, the instrument then opened, and both blades cut their way to the desired extent of {150} incision; finally, the tracheotome of Maisonneuve, a curved dilating hook with cutting inner edges. Its point is entered between the first and second rings of the trachea and brought out again between the fourth and fifth; the handle is then carried under the chin, so that the blades are made to cut through the trachea and the skin between the points of insertion and exit, after which, upon pushing a spring, the two halves of the hook separate, and the canula is introduced between them (Thornton). And the trachea-stretcher of Marshall Hall, by means of which a portion of the trachea is cut out and the opening kept patent. None of these instruments have been proven to possess any practical worth; on the contrary, their use, especially that of the latter forms, has in more than one instance been attended with disastrous results.