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(4) That some animals attain absolute immunity, resisting even two fixed virus and one
street virus subdural inoculations during a period of nine months.
(5) That other animals exhibit only partial immunity showing tremors and well marked.
paralysis of the hind quarters after the test inoculation, whether it be subdural or subcutaneous..
This paralysis may completely disappear or become permanent. In either case the animal
resists a further intraocular injection with street virus.
(6) That in no case can one be certain of immunising a guinea-pig either by single or
multiple doses of fixed virus against either subcutaneous or intraocular injection of first passage
street virus brain.
The susceptibility of the guinea-pig to both street virus and fixed virus limits in some
directions its use in determining the value of modifications of treatment designed to be applied to.
less susceptible animals. On the other hand, a system which proved safe and certain in the case
- of the very susceptible animal could be fearlessly applied to the less susceptible.
10. THE ACTION OF CHLOROFORM ON FIXED VIRUS.
BY
W. COKNWALL AND M. KESAVA PAI.
The object of this experiment was to ascertain whether it would be possible to preserve au
emulsion of fixed virus for a few days by means of chloroform so that it might be distributed on
occasions from a centre for local use.
lt is at present not practicable to prepare sterile emulsions of rabic cord substance.
The usual methods of grinding the fragments in a mortar or pounding them in a conical glass,
however quickly performed, allow a certain number of air-borne organisms to fall into the
emulsion. Such emulsions cannot be bottled and sent out without a great risk of decomposition
occurring, so any machine which could prepare sterile emulsions of differing strengths or any
chemical which could inhibit bacterial growth without harming the vitality of the rabies
organism would be of considerable value.
A 1 i n 5 0 f i l t e r e d t h r o u g h p a p e r e m u l s i o n o f f i x e d v i r u s w a s p r e p a r e d a n d c h l o r o f o r m
vapour bubbled through it for 20 minutes. Samples were then taken and sealed in glass-
bulbs. Sterile air was next bubbled through the emulsion until the chloroform was removed and
further samples were taken. Rabbits were inoculated subdurally after the samples had been
kept in the ice box for 24 hours and 7 days, respectively.
TABLE NO. 16.
Emulsion 1 in 50 fixed virus
how treated.
Result of subdural inoculation of rabbits with the emulsions.
Incubation period in days.
Series 1.
Series 2.
Series 3.
7 days in
ice box.
24 hours in
ice box.
7 days in
ice box.
24 hours in
ice box.
7 days in
ice box.
24 hours in
ice box.
1. Untreated emulsion as control ...
2.
Do.
do.
6 days ...
7
7 days ...
7
6 days ... 6 days ... 7 days ...
1. Emulsion treated with CHCl 3 ... ...
2.
Do.
do.
Survived ...
Do. ...
Survived ...
Do. ...
7 days ...
...
Survived ...
...
_
Survived ...
...
A b a n d o n e d .
1. Emulsion treated with CHCl 3
and air bubbled through to
remove it.
2.
Do.
do.
Survived ...
8 days ...
Survived ...
8 days ...
7 days ... 7 days ...
...
Survived
..
As shown by Table No. 16 sometimes the virus was destroyed by the chloroform and sometimes.
it was not, and a greater effect was produced when the emulsion was sealed up saturated with the
vapour than when the vapour had previously been removed by sterile air. In every case the
samples were proved to be sterile as far as bacteria were concerned by plate cultures. Assuming
the principle that in order to obtain effective immunity against rabies the material inoculated
must contain the organism in the living state, and finding that it is more often destroyed by
chloroform vapour than not, the experiment was abandoned.
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