A Paper on POLIOMYELITIS *

A notable advance in knowledge may raise as many questions as it solves, and a period of intensive and fruitful research may at first sight seem to leave us as far as ever from the solution of the problem we are in vestigating. This might plausibly be said of poliomyelitis. Few affections of the nervous system have been more closely or successfully studied within the past few years, yet fresh pathological and epid?miological factors appear for elucidation, effective therapy remains as remote as ever, and many of our earlier certitudes have gone by the board. Yet we must necessarily be nearer a grasp of the many problems presented by poliomyelitis, and the present time is appropriate for a review of some recent advances in our knowledge. A comprehensive summary of these is not possible within the limits of my present opportunity, and I propose, therefore, to confine myself to a brief consideration of the question of the specific treatment of the disease in the light of our rapidly changing conception of its nature. By way of definition we may say that poliomyelitis is one of a small group of infections of the nervous systems due to the action of ultra-microscopic viruses, the morpho logical identities of which are unknown to us. Other examples of the group are epidemic encephalitis and rabies, and in all three it is the grey matter which is the point of attack, whence these viruses are spoken of as " polioclastic." Of the characteristics they have in common perhaps the most striking are that they multiply only in contact with the living cell, within which their life and activity appear to be very brief, for after a short period they disappear. To this disappearance the name " auto-sterilization " has been applied, and in consequence of it virus diseases may be spoken of as " self-limiting."