(c) Syphilitic and tubercular laryngitis are other inflammatory affections of this tube, but the inflammatory diseases presenting themselves most frequently are membranous croup and diphtheria.

As results of these various attacks of inflammation we may have, as we have already seen, œdema, or, if the case is prolonged, ulceration, and necrosis of the cartilages or laryngeal phthisis, and from the healing of the ulcers we may have strictures. Strictures also result from a deposit of fibrin in the submucous cellular tissue, from contractions following a wound, and from the pressure of tumors.

2d. Often entirely independent of inflammation occurs another disease termed spasm of the larynx. Familiar instances of this affection are seen in spasmodic croup and when a drop of water enters the windpipe. Spasm of the larynx results as a consequence of many diseased conditions of this organ, and even from causes external to it, such as tumors pressing on the recurrent laryngeal nerves or reflex irritation from diseases of the stomach, bowels, and uterus, and in fact from a great variety of causes. In all diseases of the larynx the patient is more or less harassed by spasm of this organ. It complicates the inflammatory affections of the larynx, and occurring during the progress of these diseases often proves. fatal. For, as Erichsen' has said, "It is of importance to bear in mind that death may occur in these cases, although a considerable portion of the cavity of the larynx continues free." Thus Dr. Cheyne states that there is always in croup at least three-eighths of the cavity of the larynx open for the transmission of air, and that death must consequently result from some other cause than mere mechanical obstruction.

3d. Abnormal growths in the larynx, such as polypus, warts, excrescences, cystic tumors, etc., may all require the aid of tracheotomy to save life.

4th. Another disease sometimes requiring tracheotomy is comparatively rare, and is known as paralysis of the larynx and trachea. It may be sympathetic, depending upon disease in other organs, or caused directly by violence or disease.

5th. Pressure from tumors, abscesses, and aneurisms on the trachea or larynx may sometimes, although rarely, require the aid of this operation.

6th. Foreign bodies, such as masses of food, buttons, etc., held in the mouth frequently enter the larynx during sudden inspiration, and are, next to inflammatory diseases, the commonest cause for the performance of tracheotomy. Of the treatment of these diseases

apart from tracheotomy it is not our purpose to speak, merely mentioning them in order to call your attention to the great frequency and urgency of the diseases and accidents requiring this operation.

Before proceeding to describe the operation and merely to refresh your memory, I would invite your attention to some details of the anatomy of the parts involved in its performance.

The larynx, whose superior opening is known as the glottis, is the upper and first portion of the windpipe. It extends from the os hyoides and base of the tongue to the trachea, forming a projection on the front and upper part of the neck in the median line. The larynx is composed of nine cartilages, three of which it is important to remember, the thyroid, the cricoid, and the epiglottis, and is lined with mucous membrane. Between the cartilages and this membrane is a cellular tissue which is liable to infiltration.

The thyroid cartilage projects in the middle line, forming what is known as the pomum Adami.

The cricoid cartilage is much smaller than the thyroid, and may be felt in the thin subject just below the thyroid, to which it is connected in the middle line by the crico-thyroid membrane, which may be felt as a soft depression between these cartilages, and is the membrane cut in laryngotomy.

The epiglottis is placed behind the base of the tongue at the upper part of the larynx, and serves to cover the opening of this organ or glottis during deglutition.

The trachea commences at the cricoid cartilage and extends downwards to the bronchia. It is about four or five inches in length in the adult, although not more than two and a half inches are above the sternum, and three-quarters of an inch to an inch in diameter. It is composed of from sixteen to twenty incomplete cartilaginous rings, each being imperfect behind and the ring completed by fibrous membrane. It is lined by a mucous membrane.

The trachea is nearest the surface at its upper part, but deepens as it goes towards the chest, so that it is an inch or more in depth near the sternum, but in short-necked fat children and in emphysema this depth is frequently increased, adding to the difficulty of the operation.

Passing now to the parts covering the trachea and involved in this operation are the skin, fat, superficial fascia, and cervical fascia, beneath which we find the sterno-hyoid and sterno-thyroid muscles, their inner edges forming the middle line. On separating these muscles from above downwards we find the thyroid cartilage, the crico-thyroid membrane, the cricoid cartilage, the trachea, and the

thyroid gland. This gland consists of two lobes placed on each side of the upper part of the trachea, which are connected by a narrow band which crosses the trachea and usually covers three or four of its upper rings called the isthmus.

The thymus gland is another organ located at the lower part of the trachea, which, however, is only met with in the infant, in whom it sometimes ascends along the front of the trachea as high as the lower border of the thyroid gland.

The blood vessels met with in this region are of great importance. Commencing below, we find directly above the sternum and overlying the trachea, the arteria innominata, one of the largest bloodvessels in diameter of the body. Then on either side of the trachea, and diverging as they ascend, are the common carotids. These three vessels need not be dreaded if the operator does not approach too closely to the sternum and confines his incisions to the median line; but if compelled by untoward circumstances to cut low, let him remember that "the episternal or interclavicular region is a locality traversed by so many vitally important structures gathered together in a very limited space, that all operations which concern this region require more steady caution and anatomical knowledge than most surgeons are bold enough to test their possession of.”

In addition to these vessels we meet with the two superior and the two inferior thyroid arteries which supply the thyroid gland and the adjacent parts. Occasionally, but rarely, a middle thyroid artery exists which passes upwards along the front of the trachea, and, last, crossing the cricoid thyroid membrane runs a small vessel, the crico-thyroid, a branch of the superior thyroid.

The superficial veins are the anterior jugulars, which run on either side of the median line, and often have communicating branches. They are of large size, and if cut give rise to troublesome hemorrhage. The position and number of these veins are subject to variation, but in making our incisions they can easily be avoided.

The deep-seated veins are the superior and middle thyroid. This last is formed by the convergence of the veins of the thyroid gland, and runs along the middle of the front of the trachea. In addition to these, and covering the isthmus, a venous plexus is formed between the veins of the opposite sides.

Having thus hastily reviewed the anatomy of the region concerned in tracheotomy, we will now consider the instruments usually required in its performance. These consist of a small sharp scalpel

Maclise, Surgical Anatomy, p. 28.

with a good point, a blunt-pointed bistoury, a director, a tenaculum, a pair of sharp-pointed straight scissors, dissecting, torsion, and dressing forceps, two blunt hooks or curved spatulæ, a dilator, a canula adapted to the age of the patient with tape to secure it, a small sponge probang, a gum-elastic bougie of a size which will pass through the canula, a syringe and tube to pass into the trachea to use if the operator fears to apply his mouth to the wound to suck out the blood from this organ. In addition to these, adhesive plaster, sponges, water, and towels will be required.

Two of these instruments are peculiar to the operation, the dilator or dilating forceps, and the canula. A number of dilators have been recommended by different inventors, but the one I have been in the habit of using, and which I have found very valuable, is this instrument which I show you. It is curved at a right angle, has three branches of equal length which are grooved on the inside, and it opens by pressure.

The canula has also been greatly modified by different operators and instrument-makers; but, without describing these varieties, I would recommend the ordinary double canula with the improved neck plate of Mr. Rogers, which is made in such a manner that while the neck plate is fixed the tube is allowed to partially follow the motions of the trachea. The most important point, however, to attend to in the canula is that it should be double, that the inner tube may be removed and cleansed without disturbing the outer one. The use of the single canula is always attended with danger from its inner orifice becoming clogged with inspissated glutinous mucous discharges, which, if not removed, will close the tube and cause, as has repeatedly happened, the death of the patient. This will be referred to again. The surgeon should be provided with canulas of various sizes, and use the largest one that can be introduced without difficulty into the trachea.

Before proceeding to consider the operation a question presents itself: shall we or shall we not use anæsthetics? Much has been written in regard to the propriety of their use in tracheotomy; but, with the exception of their influence on the respiration, the same rules hold good for their administration in this as in other operations, and I would urge their employment in all cases except those in which the patient is asphyxiated and nearly or quite insensible, or in those of sudden suffocation; in these the anesthetic is not only uncalled for, but would be positively injurious, adding greatly to the danger of the patient. But when these conditions are not present, and when we have sufficient time, the operation is greatly facilitated by the use of ether, which, after the first irritation

produced by it passes away, allays the spasms of the larynx and renders the respiration easier, thus saving the surgeon from the difficulty and danger of operating upon a struggling patient and relieving the operation of much of its terror.

Under the general name of bronchotomy three operations are usually described, viz.: 1st, laryngotomy; 2d, laryngo-tracheotomy; and 3d, tracheotomy.

1. We will commence with laryngotomy as being the one most easily and quickly performed and with the least danger, the opening into the windpipe being made through the crico-thyroid membrane. The patient may, if an adult, sit in a chair with his head thrown back and supported by an assistant, or he may lie on a narrow table properly prepared, with the shoulders and back of the neck so supported by a firm pillow as to throw the head backwards and make the trachea prominent; or if a child, he may be placed on the lap of an assistant who may control his movements by wrapping him in a sheet or shawl.

Having placed him in either of these positions and in a proper light, the head should be held back and steadied by an assistant. If the patient is sitting, the surgeon should take his position in front of him, or, if lying down, on his right side. Having ascertained the exact location of the crico-thyroid space and secured the larynx with the thumb and fingers of the left hand, the skin and cervical fascia should be divided by a small scalpel, commencing the incision near the top of the thyroid cartilage in the middle line and carrying it downwards just beyond the cricoid, making an incision from an inch to an inch and a half in length, and exposing the crico-thyroid membrane and the artery of the same name which crosses it. As soon as the incisions are made, the edges of the wound should be kept apart by retractors, which facilitates the operation. If the artery should be divided and the hemorrhage prove troublesome, it may be ligated or twisted, but pressure is generally sufficient to arrest the bleeding, which should always be cheeked before the membrane is cut, except in urgent cases. Having arrested the hemorrhage, the membrane should be divided by the knife in the same direction as the external wound, or transversely, which is recommended by some and has its advantages, making a free opening large enough to admit the tracheal tube, which should now be inserted if the case is one which requires it. This, however, is not always an easy matter, as may be inferred from the statement of Mr. Durham "that cases have occurred in which the canula has been passed

'Holmes's Surgery, vol. ii. p. 500.