LEPTOMEN1NGIT1S. 



421 



Leptomeningitis : In leptomeningitis the inflammatory proc- 

 ess nearly always involves the arachnoid and pia of both brain 

 and cord*. The condition may occur as an epidemic cerebro- 

 spinal meningitis; or in the course of smallpox, scarlet fever, 



FIG. 193. 



Hydrocephalus interims ; dilated ventricles (U. S. A. Museum, No. 8233). 



pneumonia, septicaemia, and other infectious diseases. The 

 pneumococcus is the organism most frequently found asso- 

 ciated with the disease, having been met with in 60 per cent, 

 of all cases. 



