INTRACELLULARIS 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 
oceurring 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 2c.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 hyperemia 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 accom- . 
