541 
1908-9.] The Pathogenesis of Micrococcus melitensis. 
animals, which is quite typical of this form of infection in either guinea- 
pig or rabbit, and the post-mortem results that are usually obtained : — 
Guinea-pig, Male. 
11*2 
4 p.m. 
A.C.E. was administered, and a 6 mm. trephine circle was cut from 
left parietal bone. 
Four (4) loops of 3-day old agar cultivations of M. melitensis from 
spleen of guinea-pig 18, emulsified in 0’2 c.c. sterile saline 
solution, injected into substance of left cerebral hemisphere. 
Disc of bone replaced, also periosteum, skin incision sutured, and 
wound sealed with cotton- wool and collodion. 
12 p.m. 
Appears quite well. Has eaten well since inoculation. 
12-2 
9 a.m. 
Is huddled up in one corner of cage ; is not eating ; hair dull and 
standing on end ; is obviously ill. Has lost 60 grammes in 
weight. 
13*2 
Condition apparently unchanged. Has lost a further 60 grammes 
in weight. 
10.15 a.m. 
Is now grinding teeth, moves slowly, and, if turned on back, rights 
itself very slowly. 
10.30 a.m. 
Generalised spasms result if touched ; convulsive movements occur 
from time to time even in the absence of obvious stimuli. 
1 p.m. 
Much worse ; marked paresis of hind quarters. 
2 p.m. 
Convulsive “ circus ” movements occur from time to time, the 
animal dragging itself round “ clockwise ” by means of its fore- 
paws. 
9 p.m. 
Quiet in corner of cage ; breathing laboured. 
14-2 
9 a.m. 
Apparently unconscious, lying on side ; if placed on legs is unable 
to stand, and falls down after feeble convulsive movements ; 
once more becomes still. Breathing shallow and slow. 
11.30 a.m. 
Condition unaltered. 
11.45 a.m. 
Still in same position as when last looked at. Is now dead. 
Post-mortem Examination. — Scalp Incision . — Scalp wound healthy in 
appearance, lips of incision healing by primary union ; no signs of pus 
visible in wound ; no stitch abscesses. 
Subcutaneous tissue occupied by oedematous and jelly-like exudation 
marked here and there with small hsemorrhages. 
Bone . — The disc of bone is firmly fixed in situ by serous exudation in 
which the periosteum is also involved. On raising the disc of bone no 
protrusion of meninges, etc., occurs. 
General congestion and injection of the vessels of the dura mater, the 
site of inoculation being marked out by an area of bloody lymph roughly 
corresponding in size and shape to the circle of bone removed from the 
calvarium. On removing the meninges a thick layer of yellowish lymph is. 
seen adhering to the surface of the convolutions in the left parieto-occipital 
region (this microscopically consists of a dense mass of large mononuclear 
leucocytes, permeated throughout by masses of cocci), cerebral vessels greatly 
engorged, numerous petechial hsemorrhages visible on the surface of the 
brain. 
