PATHOGENESIS 37
human beings, then my belief that human infection takes place by way of the alimentary canal is not without foundation, for the paralysis almost always attacks first the legs and often remains confined to them.
Hoche believes the central canal of the nervous system plays a part in the pathogenesis, but it is difficult to understand the reason for his faith. If the morbid changes have any relation to the special infective process, presumably, a communication must exist between the site of infection and the central canal. Otherwise, only diffusion of the process within the spinal cord itself could be ascribed to the central canal. But the facts satisfactorily show that the central canal has no great importance. In some cases of acute poliomyelitis, elderly people in whom the central canal was obliterated, have been attacked; and in cases where the canal was patent, in and around it, extremely slight and not always definite pathological changes occurred. As in my early investigations, I paid special attention to the central canal and myself demonstrated these points. I consider there is no sound basis for Hoche's opinion. The tendency to attack children is peculiar to all infectious diseases and can hardly be connected with the patency of the central canal.
