Diseases of the nervous system form a somewhat obscure branch of medical science. Our ignorance of the morbid anatomy and histology of many of them is profound. It is, accordingly, a matter of no surprise that our classification of these diseases is unsatisfactory. The intimate correlation between nervous and muscular systems is recognized in the fact that under nervous diseases, every textbook includes descriptions of conditions which are, so far as known, essentially muscular.
There is a tendency to segregate those cases which show muscular atrophy into two clinical groups, the atrophies and the dystrophies. The distinction is probably not well grounded, in respect to etiology. In view, however, of our lack of knowledge of the cause of most of the nueuromusclar diseases, even this criticism must be made somewhat tentative. We can recognize the grosser causes of lack of function of the central nervous system, such as cerebral hemorrhage,