TBACERY. 391 TRACHYTE. styles of tracery, which give the key-note to each, aiiil liy means of which the merging of one style into the other can he traced. During the Deco- rated period the tracery Ijecame more varied in form, being composed of squares, triangles, and other forms, filled with foils and having the ap- pearance of being packed together. This kind of tracery is called 'geometric' The windows of the transition from Decorated to Perpendicular had tracery of a more flowing character, while that of the Perpendicular (q.v.) period became almost entirely composed of vertical lines. The 11am- lioyant (q.v.) or contemporary style in France had tracerj' of a very ditVerent description, be- ing as free and graceful as the other was straight and stiff. See Gothic Art. TRACHEA (Neo-Lat., from Lat. trachia, from Gk. rpaxcia, tracheia, trachea, Aindpipe, rough arterj', so called because of the rings of gristle, from rpaxiJc, trachys, rough), or Wind- pipe. The tube through Avhich air-breathing vertebrates receive air into the lungs. It extends from the throat to the bifurcation of the bronchi. It is sufficiently described in the article Respi- ration. Tracheotomy (q.v.) is necessary for the removal of foreign bodies lodged in the trachea and bronchi. The trachea shares certain intlam- mations and morbid processes in common with the larynx and the bronchi. For figure of trachea, see Broncuus. TRACHEID. Usually elongated, taper- pointed, woody cells, resembling tracheae in ap- pearance, but not forming, a continuous vessel. T)ie wood of many conifers consists almost ex- clusively of tracheids. See Histology. TRACHEOTOMY (from Gk. rpaxem, tra- cheia, trachea, windpipe, rough artery + to/ij/, tome, a cutting, from -e/jveiv, temnein, to cut) and Laryngotomt (from Gk. Puo/jcj-f, lart/nx. larynx + '"/"/, to)ne, a cutting). Opening the trachea by incision in order to admit the en- trance of air when suffocation is threatened. Among the conditions Obturator which demand trache- otomy are foreign bodies in the air passages, cut throat, diphtheria, cedema of the glottis, and tu- mors either within the larynx or pressing upon the air passages from without (as a goitre). The air pas- sages may be opened in three different situations — namely, through the crico- thyroid membrane ( see Larynx), when the operation is termed laryngotomy ; through the cricoid cartilage and the vipper rings of the trachea, the oper- ation being known as laryngo-tracheotomy : and through the trachea, below the isthmus of the thyroid gland, constituting tracheotomy proper. LarjTigotomy and tracheotomy are more common- ly performed than laryngo-tracheotomy. to which DO further allusion is required. Laryngotomy is INSTRUMENTS FOR INTUBATION. more quickly and easily performed, especially in adult males, and is less dangerous: tracheotomy is a more difficult, tedious, and dangerous opera- tion, but must be employed in some cases (as, for example, where there is any necessity for intro- ducing the forceps and in eases where a tracheotomy tube must be allowed to remain in position for some time). The incision is made in the middle line of the neck, longitudinally, the blood vessels being pushed aside as much as possil)le with the handle of the knife. When the trachea is exposed and is cut through the wound is held apart with tcnacula that the tube may be inserted. As haste is generally necessary, a neat dissection can rarely be made, but great care must be exercised to prevent blood from en- tering the air passage. When the operation is completed a large curved tube to breathe through is inserted in the aperture, and secured round the neck with tapes. A double tube or canula possesses many ad- vantages, as, by withdrawing the inner one, which should slightly project at its lower ex- tremity, it may be cleared of any mucus or blood that may have accumulated in it, without dis- turbing the wound. The calibre of the inner tube slinuld always be sufficiently large to admit as much air as usually passes through the chink of the healthy glottis. If left too long, the patient may die of asphyxia. It is therefoie necessary to decide and act quickly, selecting a field of operation certainly below the point of obstruc- tion, and a full-sized tube should be inserted. Up to the time of O'Dwyer the operation of tracheotomy was frequently and successfully per- formed. In 188.5 Dr. .Joseph O'Dwyer of New York devised instruments wherewith intubation of the larynx was performed as a substitute for traclieotomy. Intubation consists in placing a short tube in position in the larynx, between the vocal cords, its lower end reaching a point as low as an incision would be made if the air pas- sages were opened, and thus admitting air from the throat. The tube may crowd down false membrane ahead of it, and in some such cases tracheotomy may be necessary. Few other dangers are possible. The tube may be re- moved on the fourth day, or may remain in situ till the eleventh day. Its presence causes disintegration of the pseudo-membrane of diph- theria ; prevents reflex spasm ; and also obviates the granulations which are common and very annoying after tracheotomy. If ulceration be produced by intubation it is superficial and trivial. The recoveries from diphtheria in cases in which intubation is practical average over 50 per cent. TRACHINL?E, trii-kin't-e (T.at. nom. pi., from Gk.Tpaxlviai, women of Trachis) . A tragedy by Sophocles describing the death of Hercules, caused by the poisoned coat of Xessus. sent to him by Deianira, in jealousy of the captured lole. The play takes its name from the chorus composed of women of Trachis. where Deianira is awaiting the return of her husband. TRACHOMA, tra-kiVma. A disease of the conjunctiva. See Cox.iuNCTmTis, section on (1 rail u la r Co nitmctivitis. TRACHYTE, tralut or trak'It (from Gk. TpaxI'ilC. trarhytes, roughness, from rpaxi'Ct trachi/s. rough). An igneous rock of porphyritic
