forceps must be kept on. In packing, never use more than one piece of gauze, so as to avoid leaving in a forgotten piece. Upon opening the dura cerebrospinal fluid flows out, the stream being increased with each expiration. Absence of pulsation of the brain points to tumor, and a livid color indicates subcortical growth. An old laceration is brownish. If the brain bulges through the opening, it means increased pressure (tumor, abscess, effusion into the ventricles, etc.). After opening the dura employ no antiseptics except normal salt solution, especially when the surgeon intends using electricity to locate a center. Remove any abnormal brain-tissue which is found. In operating for tumor the dura is opened and in some cases the brain is incised. The tumor is turned out by the finger, or, if this is impossible, by the dry dissector, the scissors, or the sharp spoon. If the entire tumor cannot be removed, take away as much as possible. The removal of a portion retards the growth of the remainder (Horsley), and the trephining, by lessening cerebral pressure, relieves the symptoms and prolongs life. After removing a tumor arrest distinct points of bleeding with the ligature alone or the ligature passed around the vessel by means of a needle. Pack the tumor-cavity with gauze and bring the end of the plug out of the wound. Stitch the dura with silk and suture the scalp with silkworm-gut. In electrifying the brain faradism is employed of a strength about sufficient to move the thenar muscles when applied to them. The current is applied to the motor area by the double electrode. A careful observer watches the muscular movements. If, for instance, the surgeon wishes to remove the thumb-center, he moves the electrode from point to point until he obtains thumbmovements. The region is sliced away bit by bit until the current applied to this zone no longer causes thumb-movements. It will be found impossible to remove only the thumbcenter. Adjacent centers are sure to be more or less damaged, and a certain amount of paralysis follows the operation. If we wish to tap the ventricles, Keen directs that the trephine-opening be one and one-fourth inches behind the external auditory meatus and the same distance above the base-line of Reid (Fig. 179, a). A grooved director or metal tube is passed into the brain in the direction of a point "two and one-half to three inches above the opposite meatus." normal ventricle will be entered at a depth of two to two and one-fourth inches, but the dilated ventricle will be entered sooner (Keen). The moment of entry is marked by lessened resistance and a flow of cerebrospinal fluid. Drainage can

The

be maintained by introducing a rubber tube. This operation has been employed in hydrocephalus. After an aseptic cerebral operation, as a rule, do not drain unless hemorrhage has been considerable. In many cases replace the bone, but not when the bone is diseased, is infected, or is very compact, or if it is desired to alter pressure. The dura is sutured by a continuous silk suture (Fig. 177); the scalp is sutured by interrupted silkworm-gut sutures (Fig. 178).

FIG. 177.-Continuous suture.

FIG. 178.-Interrupted suture.

Operation for Mastoid Suppuration.-The instruments required in this operation are a scalpel, a gouge, a chisel, a mallet, curets, a probe, a dissector, dissecting- and hemostatic forceps, and needles. Provide a sand bag to place under the neck. An incision is made one-quarter of an inch posterior to the auricle and down to the bone, and in the direction of the long axis of the mastoid. The bone is bared and examined, especially at a point in the line of the incision which is on a level with the roof of the meatus (Fig. 179, c). The bone will usually be found softened. Gouge it away and thus open the mastoid antrum. This bone-opening is within the limits of Macewen's suprameatal triangle, a space bounded by the posterior root of the zygoma, the posterior bony wall of the meatus, and a line joining the two. If the mastoid is opened in this triangle, the antrum is entered directly and there is no chance of wounding the lateral sinus. If, in the adult, pus is not found on opening the mastoid antrum, gouge downward and backward, but with great care, so as to avoid the lateral sinus. After evacuating the pus, scrape out the cavities with the curet, enlarge the opening between the mastoid and the middle ear with the gouge, turn the head toward the side operated upon, and irrigate the mastoid with corrosive-sublimate solution (1:2000); dust in iodoform, pack with iodoform gauze for a few days, and then introduce a silver drainage-tube. Treat the causative ear disease. A. Marmaduke Sheild and Macewen operate on inveterate cases of mastoid disease as follows: a thick flap is raised behind the auricle, the flap including the orifice of any sinus and being "left attached by

its stalk." The auricle is "detached forward and the soft parts over the mastoid are turned backward by horizontal incision." The "lining membrane of the canal is separated from the bone." The mastoid is opened and dead bone and caseous matter are removed, overhanging edges are chiselled down, and the posterior bony wall is gouged away.

FIG. 179.-Opening the mastoid antrum and the lateral sinus; exposure of the temporosphenoidal lobe and puncture of the descending horn of the lateral ventricle: a, temporosphenoidal lobe (descending cornu of lateral ventricle is 1 cm. deeper); ¿, inner surface of periosteum; c, mastoid antrum; d, lateral sinus (Kocher).

The skin-flap is pushed into the cavity and is held in place with pads of gauze. The margins of the flap may be sutured, but this is not necessary. Macewen calls this procedure "papering" the cavity with skin.'

If mastoid suppuration has established abscess in the temporosphenoidal lobe, trephine one and a quarter inches behind and one and a quarter inches above the middle of the external meatus (Barker's point, Fig. 179, a), and search 1 Lancet, Feb. 8, 1896.

1

for pus as directed on page 562. If abscess of the cerebellum exists, trephine below the line of the lateral sinus-that is, below a line running from the inion to a point on a horizontal line from the roof of the meatus, one inch posterior to the middle of the meatus. If infective sinus-thrombosis exists, break into the lateral sinus (Fig. 179, d) through the mastoid opening and proceed as directed on page 564.

Linear Craniotomy.-Instruments as for any brain operation, plus, however, several kinds of rongeur forceps. Make a large flap. Trephine the skull a finger's breadth from the sagittal suture, and the same distance back of the coronal suture. Rongeur the bone away in a line parallel with the sagittal suture up to a point in front of the lambdoidal suture. Remove the pericranium which covered the bone excised. Insert the dural separator, or pass it along the margins. In some cases an additional portion of the bone is removed over the fissure of Rolando. Various suggestions have been made as to the direction and situation of bone-sections. Bleeding is arrested and the flap is closed without drainage.

Removal of Gasserian Ganglion (page 533).

Operation for Infective Sinus-thrombosis (page 564).

XXIV. SURGERY OF THE SPINE.

Congenital Deformities.-Spina bifida, or hydrorrhachitis, is a congenital cystic tumor due to vertebral deficiency, permitting protrusion of the contents of the spinal canal in the median line. The laminæ or spines of one vertebra or of several vertebræ may be deficient, most frequently in the lumbosacral region. Meningocele is a protrusion of dura mater and arachnoid, the sac containing cerebrospinal fluid, but no nerves and no cord-substance. Meningomyelocele (the commonest form) is a protrusion of dura mater and arachnoid, the sac containing cerebrospinal fluid, nerves, and cord-substance. The cord may spread upon the sacwall or it may pass through the sac and re-enter the canal. Syringomyelocele is great distention of the central canal, the sac-wall being formed of the thinned cord. A spina bifida varies in size from that of a walnut to that of a child's head; it grows rapidly during the early weeks of life; it is usually sessile, but may present where it joins the body a definite constriction, or even a pedicle; the base of the sac is covered with healthy skin, and the fundus is covered only by thin epidermis or by the spinal membranes

themselves. Pressure upon the tumor is found to diminish its size and to increase the tension of the anterior fontanelle, and possibly to cause convulsions or stupor. The cyst is translucent, and the margins of the bony aperture are distinct. Crying, coughing, or pressure upon the anterior fontanelle makes the tumor more tense. Spina bifida is apt to be associated with club-foot, with hydrocephalus, and with rectal or vesical paralysis. Spina bifida usually causes death. A few meningoceles and a very few meningomyeloceles undergo spontaneous cure by the shrinking of the sac. Syringomyelocele is invariably fatal. The cause of death may be rupture of the sac or marasmus.

Treatment. Very small protrusions which grow slowly. and are covered with sound skin may be treated by the use of a compress and bandage, by an elastic bandage, or by applications of contractile collodion. Some surgeons tap and drain the sac. Injection is used by many. The sac being cleaned, the child is placed on its side and a little chloroform is given. A fine trocar is plunged obliquely in at the side through sound skin, little or no fluid being drawn off, and 3j of Morton's fluid is injected (iodin, gr. x; iodid of potassium, gr. xxx; glycerin, 3j). The trocar is withdrawn and the puncture is sealed with a bit of gauze and iodoform collodion. The child is put to bed. If the injection proves successful, the sac shrinks; if the injection fails, it may be repeated at intervals of from seven to ten days (Jacobson, White). Many surgeons prefer excision of the sac. Bayer treats it as he would a hernia. Robson, in some cases, excises the entire sac (page 594).

Tumors of the Spine.-Among congenital tumors are lipomata and cysts (dermoid, congenital, sacral, and fetal). Tubercle, gumma, psammoma, and fibroma may arise from the cord or its membranes. Glioma is the most usual growth. Primary sarcoma is rare. Angeioma may occur. Carcinoma is never primary. A tumor rarely produces obvious symptoms until it is as large as a hazel-nut.

Symptoms and Treatment.-Pain, stiffness of the back, areas of anesthesia, and progressively advancing motor paralysis are symptoms of spinal tumors. A tumor may produce the symptoms of compression-myelitis, locomotor ataxia, or myelitis. In glioma there are apt to be loss of ability to recognize variations of temperature (or even to distinguish between heat and cold), loss of the sense of pain, and paresis and atrophy of muscles. Contractures or paraplegia may arise. The location of the tumor can be inferred