the abdomen beneath the vest, so that when afterward withdrawn space will be left for abdominal respiration (Sayre's stomach pad). When the plaster case is dry it may be sawn through down the front, removed, the fronts edged with leather, and perforated with eyelet-holes, so that it can be worn laced up, and be taken off from time to time. To apply the poro-plastic felt, the jacket, which is first made to measure, must be put in a steam oven, and when rendered thoroughly plastic, further moulded to the patient, who should be prepared and suspended in the same way as for applying plaster-of-Paris. Of steel instruments, that known as Taylor's is perhaps the best. In my own practice, however, I almost invariably employ the poro-plastic jacket. Where the disease is in the cervical or upper dorsal region, Sayre's jury mast may be fitted to the plaster-of-Paris case or poro-plastic jacket; or a cervical collar composed of leather or poro-plastic felt may be used, or better, the combined poro-plastic jacket and collar devised by the author. Should an abscess form, it should be treated in the way described under Chronic Abscess. In some cases where necrosis has been associated with caries, success has attended the removal of the sequestrum through a properly planned incision made in the loin.

OCCIPITO-ATLOID, and ATLO-AXOID DISEASE, are terms applied to strumous inflammation attacking the articulations between the occipital bone and the atlas, and the atlas and the axis respectively. Hence the disease resembles in its course strumous disease of the joints, rather than strumous disease of the bodies of the vertebræ. It may begin either in the synovial membranes, or as caries of the bones forming the articular processes, and when occurring between the atlas and the axis usually affects the synovial membranes between the odontoid process and the transverse ligament on the one hand, and the tubercle of the atlas on the other. Indeed in this situation it would often appear to begin as a caries of the odontoid process itself, and then spread to the synovial membranes. The disease is often attributed to a sprain of the neck, but though it may sometimes be excited by such, would appear more probably to depend on causes similar to those leading to strumous disease elsewhere.

Symptoms.-Pain is first felt over the seat of the disease, and radiating in the course of the nerves emerging from the intervertebral foramina between the affected bones. It is increased on attempting to turn or nod the head, but is relieved by supporting the chin with the hand. Hence the patient often holds his head between the hands, and if asked to rotate it, turns his whole body, keeping his neck stiff and immovable the while. When the disease is chiefly limited to the articulations between

the occipital bone and the atlas, the pain is principally confined to the region supplied by the suboccipital nerve, and is increased on nodding rather than on rotating the head. As the disease advances, the atlas, with the occipital bone, has a tendency to slip forward on the axis-directly forward if both sides are equally diseased, or more to one side if the disease is unilateral. The spine of the axis in consequence appears more prominent than natural, and the head on a plane anterior to that of the rest of the spinal column. Should an abscess form, it may point at the back of the pharynx (post-pharyngeal) or at the side of the neck. Treatment.-Absolute rest on the back, with the head between sand-bags, is imperative, as there is danger of fatal compression of the cord from the odontoid process and the transverse ligament giving way during some sudden movement of the patient. In some cases attended with paralysis below the disease, continuous extension and counter-extension, with the patient in the recumbent position, has been successful in removing the pressure from the cord. When the acute symptoms have subsided, a moulded collar of leather or poro-plastic felt, or an inflating India-rubber collar will be required.

SPINA BIFIDA is a swelling in the middle line of the back formed by a protrusion of the spinal membranes through a congenital fissure in the neural arches of one or more of the vertebræ. It is due to an arrest of development of the lamina of the vertebræ, and their consequent failure to unite in the middle line to form the spinous processes, possibly sometimes owing to an excess of cerebro-spinal fluid. It may occur in any part of the spine, but is most common in the lumbo-sacral region, where the lamina are the latest to unite. It may be associated with other deformities, especially club-foot.

Pathology. The sac is composed of dura mater, and generally of both the parietal and visceral layers of the arachnoid adherent and blended together; sometimes of the dura mater and parietal layer of the arachnoid only. In the former case the sac will communicate with the subarachnoid space, and contain cerebrospinal fluid; and large nerve-roots, or even the spinal cord itself, will be found intimately connected with the sac (meningo-myelocele). In the latter case it will communicate with the arachnoid cavity, and the nerve-roots and cord will remain in the canal (spinal meningocele). In rare instances the pia mater and spinal cord have been found uniformly spread out in the walls of the sac, probably in consequence of the fluid having collected in the central canal of the cord (syringo-myelocele). Usually the spinal cord or cauda equina passes into the sac and is connected in the middle line with its walls, the upper nerve trunks

passing through the walls of the sac to their destination, the lower ones passing through the interior of the sac and re-entering the spinal canal.

Symptoms.-The swelling is usually of a globular or oval shape, translucent, sessile or slightly pedunculated and flaccid, but becomes tense and distended on coughing or straining. Pressing upon it sometimes causes the fontanelles to swell up, and may produce convulsions. When the spinal cord and large nerves are involved, there may be paralysis of the extremities or of the bladder or rectum. The gap between the laminæ of the vertebræ may at times be felt on pressing on the sac. As a rule, these tumors show a great tendency to enlarge, and rupture spontaneously, in which case death usually follows from the draining away of the cerebro-spinal fluid, or from septic meningitis.

Diagnosis.—Its congenital origin will at once distinguish a spina bifida from a new growth developed subsequent to birth; and its situation in the middle line, translucency, increase of tension on straining, and the gap between the lamina when this can be felt, will usually serve to diagnose it from other congenital tumors.

The

Treatment. As there are no means of accurately determining that the spinal cord is not in the sac, it is not safe to attempt excision or ligature, although these operations have at times been attended with success. Repeated tappings are very fatal. best treatment, except when the spina bifida is very small or is apparently undergoing a spontaneous cure, is to inject the sac with Dr. Morton's iodo-glycerine fluid, as this method, when successful, causes the tumor to shrink, and most closely follows the process of nature when a spontaneous cure occurs. The injection is best performed when the child is two months old; but it may be done earlier when the sac threatens to burst. It is contraindicated when there is "advanced marasmus, great and increasing hydrocephalus, and intercurrent disease." The child should be placed on its side, and the puncture made obliquely through healthy skin on one side of the base of the tumor, and not through the thin and imperfectly formed skin which nearly always covers the sac in the middle line, "the object being to avoid wounding the expanded spinal cord, and the subsequent leakage of the cerebro-spinal fluid." About a drachm of the iodo-glycerine fluid (iodine, grs. x; iodide of potassium, grs. xxx; glycerine, 3j) should be injected, and the injection repeated in a fortnight if the first trial is not successful. The fluid contained in the sac should not be drawn off before the injection. The advantage of Morton's fluid over tincture of iodine alone is

that, owing to the glycerine it contains, it uniformly diffuses itself over the sac walls. The injection of iodo-glycerine is not unattended with danger; therefore, when the sac is small and its walls are thick, and it is not increasing in size, beyond protecting it with a metal or leather shield, no further treatment should be attempted.

SURGICAL DISEASES OF THE INTESTINES.

INTESTINAL OBSTRUCTION.

The pathological conditions that may give rise to intestinal obstruction are very various, and may be considered under the following heads:

1. IMPACTION OF FÆCES OR Foreign Bodies in the INTESTINES. Obstruction from accumulation in the rectum and colon of hardened fæces, the result of habitual or accidental constipation, is not uncommon, and the impaction of gall-stones or intestinal concretions in the small intestines, though more rare, is also met with. Obstruction from these causes is more common in women than in men.

2. VOLVULUS is a twisting or bending of a coil of intestine, so that its calibre is completely obliterated at the bent or twisted spot. Accumulation of flatus and unequal distention have been assigned as a cause. The intestine may be-1, simply bent upon itself; 2, twisted round its mesentery; and 3, wound round another coil of intestine. Volvulus is said to be most common in the sigmoid flexure; and always to be situated toward the back of the abdominal cavity. The first form only occurs in the colon; the second in the small intestine; the third form usually consists of the colon wound round a coil of small intestine, the sigmoid flexure, or the cæcum.

3. INTERNAL HERNIA OR INTERNAL STRANGULATION.--These terms are applied to the obstruction of the intestine by some constricting agent within the abdomen. The strangulation may be effected by: 1. Bands produced by the stretching of old inflammatory adhesions. These are more particularly common about the mouth of old hernial sacs. 2. The remains of some foetal structure, as the omphalo-mesenteric duct, diverticula, etc. 3. A coil of intestine slipping through a hole in the mesentery

or omentum.

4. INTUSSUSCEPTION (Fig. 175) is the invagination of a portion of intestine into the lumen of the intestine immediately below. The intestine thus forms three tubes, one within the other, an outer, middle, and inner (Fig. 176). The external tube is called the sheath, the innermost the entering tube, the

middle the receding or inverted tube, the last two together being further called the intussuscepted portion. Thus there are two peritoneal and two mucous surfaces of the intestine in contact (Fig. 176), and between the inner and middle tubes is a portion of the mesentery or meso-colon, which is necessarily drawn down with the intestine. The dragging of this mesentery causes the intussuscepted portion to assume a greater curve than the sheath, and hence to become puckered along the concavity, and its orifice to be directed toward the mesenteric attachment, and to be slit-like in shape. The intussusception increases at the expense of the lower portion of the intestine, the sheath becoming more and more infolded, so that, if the intussusception occurs at the lower part of the jejunum, no more of the jejunum

will be involved, but the ileum, cæcum, and colon may be grad. ually drawn in. At first the invagination is reducible, and is not attended with any serious obstruction to the lumen of the intestine. In this condition it may remain, in chronic cases, for several weeks or months. Or the mucous membrane of the intussuscepted portion may become congested and swollen, rendering reduction difficult or impossible without rupture or other injury of the intestine. In the majority of cases, however, especially in infants, if the intussusception is not soon relieved, the blood-vessels of the involuted mesentery rapidly become constricted where the latter enters the sheath, causing acute obstruction to the circulation in the receding tube. As a consequence of this, the mucous membrane becomes intensely congested, and