INTRA CELL ULARIS MENINGITIDIS. 519 



. diplococci are found in small numbers and mostly free; 

 in the pleuritic exudation they are present in consider- 

 able quantities, less so in the peritoneal fluid, but then 

 occurring in the interior of pus-cells. 



Certain experiments made by Weichselbaum on dogs, 

 though not entirely successful, are interesting as showing 

 the similarity of the disease produced in them artificially 

 with meningitis as occurring in man. The three dogs, 

 trephined and inoculated subdurally with 0.5 to 2 c.c. of 

 afresh culture, all died: No. 1 within twelve hours, No. 

 2 in three days, and No. 3 in twelve days. In Nos. 1 

 and 2 there were found hypersemia of the meninges, with 

 inflammatory softening of the brain at the point of inocu- 

 lation, which on nearer inspection proved to be a true 

 encephalitic process. In dog No. 2, in which the dis- 

 ease was of longer duration, these changes were the 

 most pronounced. Numerous diplococci were observed 

 in the sections removed, for the most part free, but 

 some few within the pus-cells. In dog No. 3, in 

 which the disease lasted twelve days, between the dura 

 mater and the brain, at the point of inoculation, was 

 found a thick, reddish, purulent liquid; in the brain 

 itself an abscess had formed, about the size of a hazel- 

 nut, filled with tough, yellow pus, while the abscess 

 walls consisted of softened brain -substance infiltrated 

 with numerous hemorrhagic deposits, and simultane- 

 ously the ventricles on that side contained a cloudy, 

 reddish fluid, with flocks of pus; but no diplococci 

 could be demonstrated in the blood or exudations. 

 Weichselbaum suggests that under natural conditions 

 the diplococci gain access to the brain and meninges by 

 way of the nose, ear, and upper air-passages. Cerebro- 

 spinal meningitis, as is well known, is often accorn- 



