In the dropsy of the ventricles the attenuation and atrophy of the cerebral convolutions produce symptoms which approximate closely to those resulting from their experimental ablation, so that one may fairly attribute the general symptoms in the two cases to the loss of their function. Many of the attendant symptoms, and especially the aberration of smell, sight, hearing and taste, may be referred to the concomitant injuries of the basal ganglia of the brain. We need not seek in one general answer to resolve the question whether the dropsy or inflammation is the initial lesion. For our present purpose it must suffice, that dropsy with anæmia and atrophy of the cerebral convolutions and basal ganglia produce the symptoms of immobility. At the same time it is only logical to conclude that any morbid condition of the cerebral circulation or of the brain or membranes which leads to a corresponding amount of ventricular effusion, or atrophy or destruction of the nerve centres already designated, will produce the symptoms characteristic of this disease. Thus the different forms of meningitis, traumatic injuries to the cranium, chronic encephalitis, cerebral softening or degeneration, sclerosis, neoplasms of all kinds affecting the brain (cysts, cholesteatoma, psammoma, melanoma, etc.), and parasites may occasion this disease. _Prognosis._ The disease is essentially incurable. It may last for years with little change except the winter improvement, but it rarely subsides permanently. It is only in those cases in which the symptoms have been determined by a transient or removable cause, as a moderate exudation or a parasite with a short term of life that a favorable result may be looked for. Usually the improvements seen in cool seasons or stables, under good hygiene, are not recoveries but temporary amelioration only. _Symptoms in other animals._ Corresponding conditions produce similar symptoms in cattle, sheep, swine and dogs, but the disease receives less attention in these animals because they are not called on for steady work. The animals are lazy, dull, insensible to excitement, stupid, show a lack of muscular power and control, stagger or move disorderly and show tympanies or other indications of indigestion.