17
Passage number.
I Incubation
period in days.
Negri bodies.
13
12
Hippocampus Major
Cortex.
Cerebellum.
Spinal ganglia 2µ —
None.
3µ numerous.
9
Cortex ...
... 2µ
Cerebellum
... None.
15
...
•
7
Elippocampus Major
Cerebellum.
Cortex.
Spinal ganglia 1µ —
None.
2µ
29
Hippocampus Major
Cerebellum
Cortex
None.
9
Hippocampus Major None.
Cerebellum
Cortex
... 1µ — 2µ
9
Hippocampus Major
Cortex
Cerebellum
None.
9
Hippocampus Major
Cortex
Cerebellum
Numerous up to 2µ
20 (1 month in glycerine in
ice box).
11
Hippocampus Major I
Cortex
Few
2µ Few
The series shows that street virus passed through a series of dogs tends to become fixed as.
regards its incubation period. There is a remarkable change in the size of the Negri bodies
which manifested itself from the third passage onwards. At the autopsy of No. 3 a considerable
collection of fluid was found beneath the cerebral membranes and two small cysts, each containing
about • 5cc. of fluid, were embedded in the cortex. Some drops of the fluid were spread on slides
and allowed. to dry. Unfortunately these were not examined till two days later when Leishman,s.
stain showed that vast numbers of trypanosomes * about 20,u, in length were present. A
rabbit and a guinea pig inoculated subcutaneously with a piece of the brain which bad been
kept two days in the ice box at no time showed. any trypanosomes in their blood and subsequently
developed rabies in the usual way. No trypanosomes appeared in any of the succeeding dogs,
so it is probable that their presence on this. occasion was fortuitous. Whether this infection
had any influence in modifying the appearance of the Negri bodies in the subsequent animals.
it is impossible to say, but it is noteworthy that the bodies immediately became fewer and smaller..
The transference of rabies to the foetus.— A guinea pig (No. 38) inoculated subdurally
from. dog 18 (vide table 9) had an incubation period of nine days. It contained a foetus 18 c.m..
long. Sections of the foetal brain displayed no Negri bodies, but another piece was subdurally
inoculated into another guinea pig (No. 151) with the result that rabies developed in seven
days. In the brain of guinea pig No. 151 Negri bodies l,u, to 3p, were found to be numerous
in the hippocampus maj or and up to 6µ in the cerebellum. From this it is evident that the
virus of rabies is at times present in the circulating blood and is able to pass from the mother.
into the tissues of the fætus. No results have been obtained on several other occasions.
The recognition of Negri bodies in material sent for diagnosis.—Negri bodies were found.
in a portion of the brain in every case in which subdural inoculation gave a positive result
provided that the material had been sent in a proper fixing medium, i.e., acetic bichromate.
mixture. In more than one case, Negri bodies were found in the fixed material, whereas the
glycerine specimen failed. to convey rabies. These brains had been sent from great distances
during the hot weather and had been from eight days to one month en route.
When material has to be sent great distances it is probable that the microscopic method is
superior to, the inoculative.
If specimens arrived preserved only in glycerine they were fixed and sectioned in the usual
-way, but very poor preparations are thus obtained; and it is doubtful whether Negri bodies can
5