2. The fluid is absolutely clear much less frequently than is usually reported; in most eases it shows rotating turbidity, like dust in sun light: and as the disease progresses it. becomes plainly opalescent. The precipitate always contains some cells, in which mononuclear lympho cytes preponderate. This difference from the other meningitides, which had already been established by 13ernheim and :Moser, 1N-as subsequently studied by \Vidal and his collaborators and promulgated in numerous publications as cytorliagnosis. We have reason to emphasize the pri ority- of the German authors.
The determination of the pure or preponderating lymphocytosis of the fluid is valuable for the diagnosis of tuberculous meningitis: it is corroborative but not pathognomonic. A positive diagnosis can be made only by the discovery of tubercle bacilli. While this is not easily accomplished, the search is facilitated by examining, the fibrin coagulum which contains the bulk of the cells and bacteria; the longer and more carefully the search is continued, the oftener is it successful. The chief difficulty consists in the scarcity of bacilli especially at the beginning of the disease. Therefore Langer has proposed incubating the aseptic puncture fluid, in which within two u-ecks at most a proliferation of bacilli with the formation of a deposit resembling bread crumbs occurs. Of course this slow method is useful only in cases in which there can be no postmortem.
Our present knowledge of acid-resisting bacilli renders it desirable to employ-, for identification, culture and animal experiments besides microscopical examination; at least in those cases which, because of recovery, justify extreme skepticism.
The prognosis of tuberculous meningitis is almost absolutely fatal. Exceedingly few cases have been cured, at any rate cases: in which tubercle bacilli were found in the cerebrospinal fluid; and none of these were kept under observation for years, as is requisite, in view of what has been stated regarding long-continued remissions. Barth's case is conspicuous through the fact that after the child had been mentally blind and deaf nearly a year, it made a complete recovery.
yet there can be no discussion of a therapy- for tuberculous meningitis. Of course the physician should treat the symptoms of irritation particularly and not spare narcotics in case of necessity; but this question arises much less frequently' than in men ingococcus meningitis. Headache is often temporarily relieved by lumbar puncture; more is not attained by this procedure. In the few cured cases no methods were employed which had not proven futile in numerous others. We note among these, besides repeated lumbar punctures, copious depletion by leeches on the mastoid process (for eight days), and large doses of creosote. The major operations on the skull which, repeatedly tried on account of the analogy to tuberculous peritonitis, promised success have so far always resulted unfortunately; and it is still doubtful if the expectation Sokolow) still cherished regard ing this method will ever be realized.