A BACTERIAL vSTUDY OF ACUTE CEREBRAL AND 

 CEREBRO-SPINAL LEPTO-MENINGITIS. 



HERMANN HICHAEL BIOOS. 



While the infectious nature of Cerebral and Cerebro-Spinal 

 Lepto- Meningitis has been long recognized, the character of 

 the micro-organism or micro-organisms producing these alBfec- 

 tions has not been satisfactorily determined. The present bac- 

 terial study undertaken at periods when these diseases were 

 prevalent in New York may throw some additional light on 

 this question. 



The facts at hand at least clearly demonstrate that a vari- 

 ety of pathogenic bacteria may be found in the meningeal 

 exudate of both cerebral and cerebro-spinal meningitis, and 

 that these bacteria are probably the important etiological fac- 

 tors in these diseases. The investigations thus far made do 

 not confirm the a.ssumption that epidemic cerebro-spinal 

 meningitis is caused by a specific organism. 



Most of the observations here detailed were made upon 

 cases which occurred during the eight weeks ending May ist, 

 1892 and the same period in 1893. During this period for the 

 past two years meningitis in adults has been relatively fre- 

 quent in New York. The observations have almost without 

 exception been made on adults. It is also during the same 

 period (March and April), as the vital statistics show, that 

 the mortality is highest from acute lobar pneumonia, and it is 

 to this disease that lepto-meningitis both cerebral and cerebro- 

 spinal .seems most closely allied in its etiology. 



In this study only those ca.ses will be considered which were 

 characterized anatomically by an acute suppurative exuda- 

 tion in the pia, not caused by the tubercle bacillus. 



The cases of acute cerebral and cerebro-spinal meningitis 

 have been grouped together, because neither from an anatom- 

 ical nor etiological standpoint are there sufficient grounds for 

 separating them. 



