MORBID ANATOMY.--Such are some of the facts bearing upon the pathology of diabetes mellitus. Throwing out the milder type of cases, in which glycosuria is the result of an over-ingestion of saccharine and sugar-producing food--and these can scarcely be called instances of essential diabetes--it is evident that glycosuria may be produced in a variety of ways operating through the nervous system; and accordingly we may infer that there is scarcely an organ in close relation with the sympathetic system derangement of which is not capable of producing it. Among these we would naturally expect to find conspicuous alterations in the nervous centres, and yet I have never found changes in these centres after death. At the same time, others have noted meningitis, tubercular {200} and traumatic, apoplectic effusions, and tumors of the brain, especially in the neighborhood of the medulla oblongata. The alterations in the nerve-centres described by Dickinson as the essential morbid anatomy of diabetes I have looked for in vain. These changes are described as a cribriform or porous condition of the white nervous matter, said to be visible to the naked eye. The spaces thus produced are partially occupied by dilated blood-vessels, which, in turn, are surrounded by dilated perivascular sheaths and broken-down nervous matter, into which extravasations of blood have taken place, as evidenced by the presence of pigment-granules. The changes are found in the white matter of the convolutions of the brain, but fewer and larger in the central portions. The corpora striata, optic thalami, pons, medulla, and cerebellum are favorite seats for the largest and most striking holes. In rapidly-fatal cases the cavities are sometimes filled with a translucent, gelatinous substance, containing, besides vascular elements, the globular products of nervous disintegration. In the more chronic forms of the disease, as it occurs in elderly persons, the excavations are usually empty, although the elements of nervous decay are still to be found fringing the margins or collected as an irregular sheath upon the dilated or shrunken artery. There are changes in the cord similar to those in the brain, but less decided. But the most striking alteration in the cord, according to Dickinson, although not always present, is dilatation of the central canal, which in the dorsal and lumbar regions is sometimes expanded to many times its normal diameter, and forms a conspicuous object immediately after the cord is divided. These alterations have eluded the vigilance of other pathologists who have sought for them in well-determined cases of diabetes mellitus, while they have been found, on the other hand, in the nervous centres when no diabetes was present. In the recent discussion on diabetes at the Pathological Society of London, Douglas Powell[7] seemed to be the only one who was convinced that most of Dickinson's specimens were examples of positive lesions.