THE PATHOGENESIS OF PARESIS.

The pathogenesis of paretic dementia is generally held to be primarily in the nervous system, though certain toxic agencies, notably syphilis, are commonly admitted to have prepared the way. Since its apparent close relations with tabes have been brought to notice, a similar pathologic condition has been considered by many to be alike the basis of both disorders; as held by Mott, for example, paresis starts as a primary degeneration of the cortical association neurons, while in tabes the exogenous sensory spinal neurons are first affected. According to his view, both are essentially the same disease, the difference being in the portions of the nervous system involved. While the question of the primary parenchymatous or interstitial nature of the earliest lesions in paresis is still discussed and while there are not lacking able advocates of the vascular origin of the disease, there is at least the merit of novelty in