PATHOGENIC BACTERIA. 257 



ing, under the low power having a yellowish-brown color. 

 The organism should be transplanted to fresh media fre- 

 quently, as it rapidly loses its power of reproduction. Many 

 of the tubes inoculated with the original material or with 

 pure cultures show no growth. 



It is moderately pathogenic for guinea-pigs and rabbits 

 when inoculated into the pleura or peritoneum. Menin- 

 gitis and encephalitis have been produced in the dog and 

 goat by inoculation in the meninges. 



FIG. 63. 



Diplococcus intracellularis meningitidis and pus-cells. (X 1000.) 



This organism appears to be the principal if not the only 

 cause of epidemic cerebro-spinal meningitis. The lesion 

 consists of a purulent inflammation of the pia and arach- 

 noid, extending into the brain substance, over the cord, 

 and along the nerves. General invasion of the tissues of 

 the body seems not to occur, but focal areas of pneumonia 

 may be present. Spinal puncture in the lumbar region is 

 recommended as a means of diagnosis. The puncture 

 should be made early, and the fluid should be examined 

 with the microscope and by cultures. 



