The description of the operative steps which has been given, and which comprises the routine in an ordinary and easy cure, should not mislead. The operation is not always as simple and safe as would appear from what has been said. At times complicated and difficult, at times dangerous in practice from the delay involved, it demands in all, but especially in certain urgent cases, a trained hand and eye, sound anatomical knowledge, coolness, self-reliance and presence of mind on the part of the operator. Despite the greatest caution, and even in apparently favorable cases where time for dissection and deliberation is allowed, certain mishaps may occur which complicate the operation to a serious, dangerous, or even fatal degree. Some of these, as will be seen, are avoidable with care, but others may happen that are not only unavoidable, but totally unforeseen, and from their very suddenness all the more embarrassing. Accidents may occur during the dissection of the soft parts overlying the larynx and trachea, and the importance of carefully determining by palpation the location of the various parts prior to making the preliminary incision, and of studiously preserving their relation and location during the dissection, cannot be overestimated. Neglect of this precaution has in more than one instance led to the air-passages being opened through the thyroid cartilage or thyro-hyoid membrane, instead of at the intended point. It should not be forgotten also that the natural laxity of the several layers of connective tissue of the neck is much increased by their division, and that the trachea, being naturally freely movable, is thus very easily displaced from its normal position during the act of dissection; especially will this happen when unskilful attempts are made to hook aside or retract the divided structures during the operation. Thus it may easily occur that the entire trachea is drawn to one side and entirely lost, or, more commonly, is turned upon its vertical axis, and finally opened at the side instead of anteriorly in the median line. It may not be opened at all, either being altogether missed by the surgeon in his dissection, which is continued past it, even down to the vertebral column, or the tracheal tube may be passed into the tissues lying in front of the trachea, under the mistaken idea that the latter has been incised. Persistence in keeping to the median line during dissection--a golden rule in the operation of tracheotomy--will render the first accident impossible; the second may be avoided by hooking up the trachea, as has been described, before incising it. If the opening into the trachea has not been made large enough to receive the tube, as often happens to the young operator, and even to the experienced when he fears to extend his incision on account of the proximity of the thyroid isthmus, no resource remains but to carefully enlarge it, pushing the thyroid isthmus or veins from before the course of the knife.