Pathology.—Cavities of the cord may exist as congenital doubling, diverticula, or other anomalies of the central canal, or they may be secondary to acute lesions, such as abscess, haemorrhage, tumor, etc. Simple dilatation, more or less extreme, of the normal canal may occur, which is known as hydromyelia and which often is unattended by any symptoms whatever, its presence being a post-mortem revela tion. In some instances hydromyelia gives rise to symptoms identical with syringomyelia, but the essential patho logical basis of the latter disease is a cen tral gliosis of insidious beginning and slow advance. This gliosis originates as follows: In the embryo the central canal or primitive tube is quite large relatively. In the normal development of the em bryo this canal closes by gradual approx imation of its walls posteriorly, which, uniting, form the normal posterior sep tum. The anterior walls remain separate, forming the normal central canal. Inter ruption or perversion of the normal devel opment results in the formation of a cav ity. Such interruption may be localized to one or more segments, or it may ex tend for some distance through the cord. The cell-elements remain of the embry onal or glia type. They are distributed irregularly in the cavity-walls, some times occurring as nests resting upon a basement material. These ependynial and periependymal cells and neurogliar or basement tissue, later in life, through the stimulus of trauma or sonic other ex citing cause, begin to undergo tion, forming gliomatous masses. The proliferation extends from centre toward periphery and also longitudinally, usu ally in the posterior areas of the cord first. The most common locality affected is the cervical cord. This new glioina tons tissue, either from inherently di minished vitality or from or other vascular lesion incidental to the imperfect blood-supply, breaks down and a cavity results. The gliosis may not always end in cavity-formation, but may remain as a tumor or as simple glia perplasia, which, however, destroys, by pressure, the normal motor and sensory cell-bodies and their axons or axis-cylin ders quite as effectually as does the break ing-down. The tendency to cavity-for mation is said to be proportionate to the excess of cellular over basement tissue in the gliosis. Secondarily atrophy of the
muscles and various forms of peripheral neuritis are among the pathological find ings.
About two hundred spinal cords in embryos, newborn infants, and children under two years of age examined. hemorrhage into the posterior horns of the cervical cord, while not frequent after difficult labor, seems a istic condition. hydromyelia is not pathological. yet a complicated cavernous condition may develop in the spinal cord from simple hydromyelia. Jn one ease, a child of nineteen mouths, a progressive widening, of the cent rat canal occurred, combined with an increase of the nen•ogliar tissue, a distinctly ological condition. In a case of cepbalus congenital hydromyelia occurred in the cervical region, as in After reporting with histological detail several cases the writer concludes that a surely congenital neurogliar byperplasia was not found in any case. hut t hat t here seems to be some relal ion between this infantile syrimgomyelia and other abnormalities of the cerebral nerv ous syFdem. Thus it is seen that syringe " myclia may be congenital and trau matic. J. Zapper t (wiener kiln.
'Woollen., Oct. 10, 1901).
Prognosis.—There is no cure for the disease; hence an unfavorable prognosis must be given as regards recovery. The disease may progress very slowly, how ever, and a duration of twenty or more years is said to be not uncommon. The progress of the disease may be spon taneously arrested, the symptoms remit ting. Such remissions may last through several years.
Treatment.—Gliomatosis of the cord is not amenable to curative or even pallia tive treatment by any means as yet at tainable. Potassium iodide has occasion ally proved to be of service in gliomatous tumors of the brain and should be tried faithfully. Silver nitrate, gold salts, arsenic, and iodine are theoretically in dicated. Electricity has been almost in variably disappointing, except as a tonic. Change of climate, rest, and general tonic treatment offer the best prospect for an arrest of progress in the disease and the consequent prolongation of life.