In this disease there is a rapidly extending paralysis, commencing in the legs, extending to the trunk and arms, and usually causing death in a few days, but not always fatal. The pathological findings in this disease have been very various. Sometimes the most exhaustive and skilled examination has failed to discover any changes either in the peripheral or central nervous system or in the muscles, while in others vascular engorgement and exudation of leucocytes have been found around the vessels in the spinal cord; and recently MM. Pierre Marie and Marinesco (1895) have found softening of the grey substance of the anterior horns in the lumbar region, with great, infiltration of leucocytes round the vessels, the walls of which were also infiltrated. In the posterior horns what was practically the same condition was noted. By Nissl's method of staining, the ganglion cells which remained in the ventral cornua were found to be swollen, their contour indistinct with changes in the chromatic substance, and cultures from various parts of the central nervous system indicated the presence of microbes, some of which had resemblances to the bacillus of splenic fever, others being probably streptococci. The nerves showed no change. Bailey and Ewing (1896) also report capillary haemorrhages and circumvascular infiltration in the grey substance of the cord and changes in the ganglion cells, but they failed to obtain any results from culture experiments. Other observers have reported changes, both parenchymatous and interstitial, in the peripheral nerves. The spleen has been found enlarged and also the mesenteric glands, as well as the closed follicles of the intestines. All the facts seem to point to-the disease being the result of some toxin which has an elective affinity for the motor neurons of the spinal cord, sometimes exerting its harmful influence on the cells themselves more particularly, at others on their prolongations in the peripheral nerves, but what is the agency producing the toxin is at present undetermined.