NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
his opinion shows that these substances could be demonstrated in the blood of
patients, as soon as 2 or 3 days after the completion of treatment.
In seeking for a technique which would serve our purpose we were first met
with the difficulty which arises from the fact, well known to those who have
worked with rabies virus, that emulsions prepared in the same proportions
from the nervous systems of different animals injected with fixed virus may
vary somewhat in virulence. Further, it has been observed by us that emulsions
of rabies virus kept at 37° C soon lose their infective power and that this loss
is of a progressive nature. This point is illustrated in the experiments set
forth in Table 12. These experiments consisted in keeping two emulsions of
rabies virus of different strengths in the incubator at 37° C. and testing their
infectivity at varying intervals by subdural inoculation into rabbits. The
emulsions of strengths 1 in2 0 0
a n d 1 i n 1 , 6 0 0 w e r e m a d e f r o m t h e m e d u l l a
of a rabbit dead in 10 days after the subdural injection of fixed rabbit virus,
the test dose being 0.4 c. c. It will be seen from the table that even after
having been kept for one hour at 37°C. both emulsions had diminished
considerably in infectivity and that the loss was progressive until at the end
of 24 hours they were no longer infective.
Special precautions had therefore to be taken in order to guard against
these two sources of fallacy. These precautions consisted, first, in making
each day for each series of experiments a series of control experiments in
which normal salt solution was substituted for the sera which were being
tested ; and secondly, in keeping the mixtures only for either 1 or2 h o u r s a t
room temperature.
Finally, in order to arrive at a quantitative estimation of the bactericidal
power of the sera, if there was any, each was tested against several emulsions
of the virus of different strengths. The technique employed was as follows—
The blood of the person to be tested was drawn from a vein by means
of a sterile syringe. It was placed in a small conical glass and set aside to
clot. The serum was left in contact with the clot for 24 hours.
The rabies virus emulsion was prepared from the medulla of a rabbit
which had died from the effects of a subdural inoculation of fixed rabbit
virus. Only those rabbits were used which showed paralysis on the 6th day
and died on the 10th day after infection. Emulsions of the medulla of
varying strengths, as indicated in the tables, were made with sterile salt
solution. Equal quantities of these different emulsions and of the sera to
be tested were thoroughly mixed and the mixtures were kept at room tempera-
ture for either 1 or2 h o u r s ; 0 . 4 c . c . o f e a c h m i x t u r e w a s t h e n i n j e c t e d
subdurally into a rabbit. For each series of serum experiments a series of
control experiments with salt solution was made. This consisted in mixing the
14
various dilutions of the virus with an equal amount of salt solution instead of serum,
allowing these mixtures to stand under the same conditions as the serum
mixtures and then injecting 0.4 c. c. of each subdurally into a rabbit.
It is perhaps necessary to state that the method of anti-rabic treatment
which was used for the patients whose blood was tested was that elaborated
by Högyes of Budapest.
Six series of experiments were made. They are briefly stated as follows—
Series 1. (Table 13).—With sera of two patients who were still under treat-
ment, which had lasted for 9 and 14 days, respectively.
Series 2. (Table 14).—With the pooled sera of 5 patients drawn on the
day on which the treatment was completed.
Series 3. (Table 15 ).—With the sera of two patients who had completed
treatment one day and five days previously. In this series experiments with a
normal human serum were also made.
Series 4. (Table 16).—With the sera of two patients drawn 5 days and 10
days respectively after completion of treatment.
Series 5. (Table 17).—With the sera of two patients who had completed
treatment 10 days and 14 days previously. Experiments with a normal human
serum were also made.
Series 6. (Table 18).—With the serum of a patient who had completed
treatment 20 days previously.
The results of these observations are fully set forth in the protocols. It is,
therefore, unnecessary to do more than draw attention to the conclusion which
a study of the tables forces upon us, namely, that it was impossible to demon-
strate bactericidal properties in any of these sera by the methods employed
by us.
Any alteration in serum properties is entirely eclipsed by individual variation
in the rabbits, and by errors of dose. It is, however, interesting to point out
that if a quantitative method of experimentation had not been employed we might
have been misled. Thus, if we take the experiments of series 6 it is seen that
both with the dilutions of 1 in 50 and 1 in 150 the incubation period as com-
pared with the controls was delayed two days. It might be argued from this
result that a certain amount of virus in the emulsions had been destroyed, the
smaller amount left giving a lengthened incubation period. That this conclusion
would be erroneous is at once apparent from the results of the experiments with
a higher dilution, namely, 1 in 1,500. In this the serum mixture gave an incuba-
tion period of 9 days while in the control animal the incubation period was two
days longer, namely, 11 days.
Before closing this part of our subject we may in passing draw attention.
to a number of experiments, the results of which are set forth in Tables
15
19, 20 and 21 of the protocols. These observations were made in order to
ascertain if any bactericidal action towards rabies virus could be demonstrated in
the sera of a few normal animals, namely, guinea-pigs, rabbits and monkeys.
As a rule the sera were tested against fixed rabbit virus, but in one series with
rabbit and monkey sera, dog virus was used. The same quantitative method
as we have already described was employed.
A study of the tables will at once show that in no instance could any bacteri-
cidal action of the sera be demonstrated.
SUMMARY.
Experiments were carried out with the object of making a quantitative
estimation of the bactericidal action, if such existed, of the sera both of patients
undergoing anti-rabic treatment and of others who had completed the treatment.
Patients were selected at various stages. The earliest had been under treatment
for 9 days, and the latest had completed treatment 20 days previously. Our
experiments failed to demonstrate the presence of bactericidal acticn towards
rabies virus in any of the sera.
The sera of normal guinea-pigs, rabbits, monkeys and men were tested in the
same way. The results were also negative
16
Protocols .
NO. I.—PASSAGE OF RABIES VIRUS THROUGH THE DOG.
Table I.— Showing the result of the passage of the virus,of the street through a series
of dogs.
The original virus was obtained from a dog which died in Meerut showing typical
symptoms of furious rabies. The incubation period of this virus when inoculated sub-
durally into a rabbit was 11 days.
The virus had been in glycerine for three weeks before the series of passages was
begun.
Number of
passage.
Method of
inoculation.
Incubation
period in the dog.
Incubation
period in rabbit
inoculated sub-
durally.
REMARKS.
Original Dog .
. . .
...
11 days.
1
Subdural
11 days
2
, ,
1 0 , ,
3
,,
8 , ,
4
Intraocular
13 days.
5
, ,
12 „
6
, ,
11 „
7
, ,
20 „
8
,,
9 , ,
9
,,
8 „
8 days
10
,,
16 ,,
9 ,,
Piece of brain had been
24 days in glycerine.
1 1
, ,
9 , ,
8 ,,
12
,,
1 3 , ,
12 „
Brain had been 2 days in
glycerine before inocula-
tion into rabbit.
13
,,
29 „
7 ,,
17
Protocols .
No. II.—A PECULIAR FORM OF RABIES SEEN IN RABBITS AND DOGS.
I .—Rabbits inoculated subcutaneously with fixed rabbit virus .
These rabbits received subcutaneously 5 c. c. of an emulsion of fixed rabbit virus of
definite strength. It was the 230th passage from the dog and gave an incubation period
of 6 days when injected subdurally into rabbits.
Table 2.— Showing the modification of symptoms and course, by sub-passage , until true
rabies is developed.
Animal.
Amount of
virus.
Method of in-
jection.
Interval be -
tween injection
and death.
REMARKS.
A. Rabbit I (original). 0.0001 gram
of medulla.
Subcuta-
neous.
58 days
Became progressively
thinner :no paresis.
Rabbit 2, passage
from 1.
Thick emul-
sion of
medulla.
Subdural
27 ,,
Became progressively
thinner : no paresis.
Rabbit 3, passage
from 2.
Thick emul-
sion of
medulla.
Subdural
21 days
Marked paralysis : no
emaciation.
B. Rabbit 1 (original). 0.01 gram of
medulla.
Subcuta-
neous.
22 „
Rapid wasting : no
paralysis.
Rabbit 2, passage
from 1.
Thick emul-
sion of
medulla.
Subdural
8 „
Showed marked para-
lysis on 7th day.
Protocols .
2.— Rabbits inoculated subdurally with virus of the street .
These.animals were inoculated subdurally with a thick emulsion of the cerebral cortex
of dogs which had died in nature of suspected rabies. The brain had been sent to the
laboratory for diagnosis. Before injection it had been kept in glycerine for several days.
Table 3.—Showing the data of three further examples .
Animal.
Amount of
virus.
Method of in-
jection.
Interval be-
tween injection
and death.
REMARKS.
A.—WARDHA DOG.
Rabbit 1 (original) Thick emul-
sion.
Subdural
57 days
Progressive emacia-
tion : no paralysis.
Rabbit 2, passage
from 1.
Ditto
Ditto
14 ,,
Marked paralysis in
13 days.
Rabbit 3, passage
from 2.
Ditto
Ditto
1 6 , ,
Marked paralysis in
14 days.
B. RAWALPINDI DOG.
Rabbit 1 (original)
Ditto
Subdural
9 days
Very rapid emacia-
tion : no paralysis :
no tremor.
Rabbit 2, passage
from 1.
Ditto
Ditto
14 ,,
Marked paralysis on
11th day : no ema-
ciation.
C. BAKLOH DOG.
Rabbit 1 (original)
Ditto
Subdural
17 days
Rapid progressive
emaciation : no
paralysis.
Rabbit 2, passage
from 1.
Ditto
Ditto
14 „
Paralysis and tremor
marked on 12th day:
no emaciation.
NO. III.—THE SUSCEPTIBILITY OF VARIOUS ANIMALS TOWARDS
FIXED RABBIT VIRUS.
A. Table 4.—Subcutaneous injection of fixed rabbit virus into guinea-pigs .
The virus used in this series of experiments was between the 225th and 228th pas-
sage from the dog : the incubation period after subdural inoculation into a rabbit was 6
days.
A one per cent. emulsion of the medulla was prepared with sterile normal salt solution..
From this emulsion different dilutions were made as required. Each guinea-pig received a
definite amount of the virus, the quantity of emulsion being in each case made up to 5 c. c.
which were injected in two places in the abdominal region. Care was taken that the
muscles were not penetrated.
Protocols .
Animal.
Amount of virus.
* R e s u l t .
REMARKS.
Guinea-pig 1
0.01 gramme
10 days
11
„
,,
2
Ditto
13 , ,
16 „
,,
3
Ditto
Remained well
,,
4
Ditto
12 days
14 ,,
Six out of eight guinea-pigs developed
rabies.
,,
5
Ditto
10 „
Average incubation period= 11 days.
11 „
Average period between injection and
death=12.5 days.
, , 6
Ditto
9 , ,
10
„
,,
7
Ditto
Remained well
,,
8
Ditto
12 days
13 „
* The upper number=Incubation period.
The lower number=Interval between injection and death.
D 2
20
Protocols .
Animal.
Amount of virus.
* Result.
REMARKS.
Guinea-pig 9 0.001 gramme
10 days 1
1 1
„
, , 1 0
Ditto
14 „
1 7
, ,
, , 1 1
Ditto
Remained well
Five out of six guinea-pigs died of rabies.
, , 1 2
Ditto
1 1 d a y s
Two showed no definite symptoms except
loss of weight.
1 5
„
Average incubation period in 3 cases
=11 6 days
,, 13
Ditto
. . .
Average period between injection and
death in 5 cases=13.4 days.
l0 days
,, 14
Ditto
. . .
14 days
,, 15 0.0001 gramme .
. . .
41 days
, , 1 6
Ditto
Died from an
intercurrent
disease.
,, 17
Ditto
27 days
Five out of six guinea-pigs died of rabies.
29 „
,, 18
Ditto
16 ,,
One showed no definite symptoms.
1 7
, ,
Average incubation period in 4 cases=
30 days.
,, 19
Ditto
18 „
Average interval between injection and
death = 34.6 days.
2 2
„
,, 20
Ditto
59 ,,
6 4
„
* T h e u p p e r n u m b e r = I n c u b a t i o n p e r i o d .
The lower number=Interval between injection and death.
B. Table 5 .— Subcutaneous injection of fixed rabbit virus into rabbits.
The virus used was the 230th passage from the dog. The incubation period in a
rabbit after subdural inoculation was 6 days.
21
Protocols .
The same technique was used as has been described for the similar series of experi-
ments in guinea-pigs.
Animal.
Amount of virus.
*Result.
REMARKS.
Rabbit 1
0.01 gramme
13 days
1 5
, ,
,,
2
Ditto
. . .
6 8 d a y s
Four rabbits out of six died of rabies.
Three showed the peculiar emaciating
type of the disease.
,,
3
Ditto
. . .
22 days
The interval between infection and death
varied from 15 to 93 days with a mean
of 49.5 days.
, , 4
Ditto
. . .
93 days
,,
5
Ditto
Recovered
,,
6
Ditto
, ,
,,
7 0.001 gramme
. . .
63 days
,,
8
Ditto
. . .
95 days
,,
9
Ditto
...
Five rabbits out of six died of rabies
Three developed the emaciating type of
the disease.
52 days
,,
1 0
Ditto
20 „
The interval between infection and death
varied from 23 to 95 days, the mean
being 54.6 days.
23 ,,
,,
1 1
Ditto
37 ,,
4 0
, ,
,,
12
Ditto
Recovered
* T h e u p p e r n u m b e r = I n c u b a t i o n p e r i o d .
The lower number= Interval between injection and death.
22
Protocols .
Animal.
Amount of virus.
*Result.
REMARKS.
Rabbit 13 0.0001 gramme
...
84 days
,,
14
Ditto
Recovered
,,
15
Ditto
. . .
58 days
Five rabbits out of six died of rabies.
Four developed the chronic emaciating
form.
,, 16
Ditto
. . .
1 1 3 d a y s
The interval between infection and death
varied from 21 to 113 days, the mean
being 66.4 days.
,,
17
Ditto
. . .
56 days
, , 1 8
Ditto
18 „
21 „
* The upper number= Incubation period.
The lower number.= Interval between injection and death
C.—INJECTION OF FIXED RABBIT VIRUS INTO MONKEYS.
I. Table 6. Subcutaneous inoculation.
The virus used was the 230th passage from the dog: the incubation period in rabbits
after subdural inoculation was 6 days. The mid-brain, cervical cord and part of
cerebellum were used for the preparation of the emulsion, the strength of which was 10
per cent. Each animal received 5 c. c. of this emulsion, Care was taken that the muscles
were not penetrated.
Animal.
Amount of virus.
Result.
REMARKS.
Monkey 1
0.5 gramme
Died after 48
days.
Rabies.
Rabbit inoculated subdurally with emul-
sion of medulla showed marked paresis on
18th day and died on 20th day.
, , 2
Ditto
Paralysed on
75th day: died on
76th day.
Rabies.
Rabbit inoculated subdurally with emul-
sion of medulla showed paralysis on 31st
day and died on 34th day.
,,
3
Ditto
Died after 71
days
Probably not
Rabies.
Two rabbits inoculated subdurally with
emulsion of medulla both died from some
intercurrent disease.
23
Protocols .
2. Table 7. Intraperitoneal inoculation .
The virus used was the same as that which was employed in the previous series of
experiments.
Each animal received intraperitoneally 5 c.c. of a 10 per cent. emulsion.
Animal.
Amount of virus.
Result.
REMARKS.
Monkey 1
0.5 gramme
Died on 113th day Rabbit inoculated subdurally with emulsion
of medulla, remained well.
,,
2
Ditto
Developed para-
lysis on 15th day
died on 17th day.
......
,,
3
Ditto
Developed
tremor and para-
lysis on 16th day,
died on 18th day.
. . . . . .
3.Table 8. Subdural inoculation.
The virus was the same as that which was employed in the previous series of experi-
ments. Each animal received subdurally 0.3 c. c. of a 1 per cent. emulsion.
Animal.
Amount of virus.
Result.
Monkey
1
0.003 gramme
Paralysis on 8th day, died on 13th day.
,,
2
Ditto
Paralysis on 10th day, died on 13th day.
,,
3
Ditto
Paralysis on 9th day, died on 11th day.
D.— Table 9. Subcutaneous injection of dog virus into guinea-pigs .
The virus used was originally obtained from a dog of the street which had died of
furious rabies. It had been passed through two dogs in the laboratory by subdural inocula-
tion, both of these animals died of furious rabies, the incubation period of the last being
10 days. A one per cent, emulsion of the medulla was prepared with sterile normal salt
solution. From this emulsion dilutions were made as required. Each guinea-pig received
a definite quantity of virus, the amount of emulsion being in each case made up to 5 c. c
which were injected in two places in the abdominal region. Care was taken that the
injections were really made into the subcutaneous tissues and that the muscles were not
injured.
24
Protocols .
Animal.
Amount of virus.
* Result.
REMARKS.
Guinea-pig 1
0.01 gramme
16 days
17 , ,
, , 2
Ditto
8 , ,
1 1 „ Five guinea-pigs out of five died of rabies.
,,
3
Ditto
10 „
The average incubation period= 10.8 days
1 2
„
Average interval between injection and
death =13 days.
,,
4
Ditto
10 „
12 „
, , 5
Ditto
10 „
13 „
, , 6 0.001 gramme
13 days
15 „
,,
7
Ditto
, , 1 5
Four guinea-pigs out of five died of rabies.
17 „
,,
8
Ditto
17 ,,
The average incubation
p e r i o d = 1 5 . 5 d a y s .
1 8 , ,
,,
9
Ditto
Died on 12th day
from other
cause.
Average interval between injection and
death=17.5 days.
,,
10
Ditto
17 days
20 „
,,
11 0.0001 gramme Died on 18th day
from other
cause.
,,
12
Ditto
31 days
Three guinea pigs out of five died of
rabies.
3 2
, ,
Average incubation period =24 days.
,,
13
Ditto
16 „
Average interval between injection and
death =25.6 days.
18 , ,
,,
14
Ditto
Died on 8th day
from other
cause.
,,
15
Ditto
25 days
27 ,,
* The upper number = Incubation period.
The lower number= Interval between injection and death.
25
Protocols .
Animal.
Amount of virus.
*Result.
REMARKS.
Guinea-pig 16 0.00001 gramme
13
days
14
, ,
,,
17
Ditto
Died, not rabies
Two guinea-pigs out of five died of rabies.
,,
18
Ditto
Ditto
Average incubation period= 18 days.
,,
19
Ditto
2 3 d a y s
Average interval between injection and
death=19.5 days.
25 „
,,
20
Ditto
Died, not rabies.
* The upper number= Incubation period.
The lower number=Interval between injection and death.
No. IV.—AN ATTEMPT TO IMMUNISE MONKEYS BY MEANS OF SINGLE
DOSES OF FIXED RABBIT VIRUS INJECTED SUBCUTANEOUSLY.
A. Six monkeys were inoculated subcutaneously in two places with 5 c.c. of a 10 per
cent, emulsion of the medulla and cord of a passage rabbit, i, e., total dose 5 c.c. divided
into two portions. It was the 228th passage from the dog : the incubation period in the
rabbit after subdural inoculation was 6 days.
Twenty-three days afterwards each monkey, and in addition two untreated ones
r ecei ved 0. 3 c. c. of a 1 per cent . emul s i on of t he medul l a of a pas s age r abbi t , whi ch had
after subdural inoculation an incubation period of 6 days.
The following was the result :—
TABLE 10.
Animal.
Amount of virus injected
subcutaneously.
Amount of virus injecte
subdurally.
* R e s u l t .
Monkey 1
0. 5 gr amme
0.003 gramme
9 days.
12 „
, , 2
Ditto
Ditto
7 , ,
8 „
* U p p e r f i g u r e = I n c u b a t i o n p e r i o d .
Lower figure = Interval between subdural injection and death.
E
26
Protocols.
Animal.
Amount of virus injected
subcutaneously.
Amount of virus injected
subdurally.
* Result.
Monkey 3
0.5 gramme
0.003 gramme
1 1
d a y s .
1 2
,
,,
4
Ditto
Ditto
8 „
13 „
, , 5
Ditto
Ditto
8 „
10 „
,,
6
Ditto
Ditto
9 ,,
10 „
,,
7
Nil.
D i t t o
8 ,,
13 ,,
,,
8
Nil.
Ditto
10 ,,
13 ,,
* Upper figure=Incubation period.
Lower figure=Interval between subdural injection and death.
B.—Six monkeys were inoculated subcutaneously with varying amounts of fixed rabbit
virus. In each instance the amount was made up to 5 c. c. which were injected in two
places in the abdominal region. The virus used was the 229th passage from the dog (the
incubation period in a rabbit after subdural inoculation being 6 days). Twenty-three days
afterwards each animal, as well as an untreated monkey, received subdurally 0.3 c. c. of a
one per cent. emulsion of the medulla of a passage rabbit.
The following was the result :—
TABLE 11.
Animal.
Amount of virus injected
subcutaneously.
Amount of virus injected
subdurally.
* Result.
Monkey 1
0.5 gramme
0.003gramme
7 days.
8 ,,
,, 2
0.15 ,,
Ditto
7 , ,
9 ,,
* Upper figure=Incubation period from date of subdural injection.
Lower figure= Interval between subdural injection and death.
27
Protocols.
Animal.
Amount of virus injected
subcutaneously.
Amount of virus injected
subdurally.
*Result.
Monkey 3
0·05 gramme
0·003 gramme
8 days.
9 „ „
4
0·015
„
Ditto
8 „
11 „ „
5
0.005 „
Ditto
9 „
12 „
„
6
0·0015 „
Ditto
9 „
12 „
„
7
Nil
Ditto
9 „
11 „
* Upper figure= incubation period from date of subdural injection.
Lower figure=Interval between subdural injection and death.
V.—BACTERICIDAL PROPERTIES OF THE SERUM OF PERSONS TAKEN BOTH
DURING THE COURSE OF ANTI-RABIC INOCULATIONS AND AFTER
TREATMENT HAD BEEN COMPLETED.
A.—Experiments to show the effect of incubation at 37° C. on rabies virus.
The medulla of a fixed rabbit virus was finely emulsified in sterile normal salt solution.
Two dilutions were prepared, namely, 1-200 and 1-1600. These were kept at 37° for
varying intervals of time, 0 . 4 c.c. being then injected subdurally into a rabbit.
TABLE 12.
Animal.
Strength of
dilution.
Period of time
kept at 37° C.
* Result.
REMARKS.
Rabbit 1
1-200
1 h o u r
14 days
13 „
„
2
„
2 hours
8
„
11 „
* U p p e r f i g u r e = P e r i o d o f i n c u b a t o n .
Lower figure=Period between injection and death.
E 2
E2
28
Protocols.
Animal.
Strength of
d i l u t i o n .
Period of time
kept at 37° C.
*Result.
REMARKS.
Rabit
3
1-200
4 hours
...
Emaciated ; sub-passage
gave rabies.
25 days
„
4
„
24 „
Remained well
„
5
1-1600
Nil
7 days
12 „
„
6
„
Nil
7 „
10 „ „
7
„
1 hour
Died after
26 days :
not rabies.
„
8
„
2 hours
24 days
25 „
„
9
„
4 „
27 „
28 „
„
10
„
4 „
Remained well
„
11
„
24 „
Died after
54 days :
not rabies.
„
12
„
24 „
Died after
20 days :
not rabies.
* U p p e r f i g u r e = P e r i o d o f i n c u b a t i o n .
Lower figure=Period between injection and death.
B. —Experi ment s t o t est i f t he sera of pat i ent s t aken bot h duri ng t he course of
anti-rabic treatment and shortly after completion of treatment contain any
substances which kill the rabies virus.
Blood was drawn aseptically from a vein of the arm. It was allowed to clot in a
conical glass and the serum was left in contact with the clot for 24 hours.
29
Protocols.
The virus used was fixed rabbit virus—passage 225th-230th, which gave on subdural
inoculation into rabbits an incubation period of 6 days. The medulla was used.
Emulsions of different strengths were prepared with normal salt solution.
Equal quantities of the serum and of these different emulsions were mixed and the
mixtures kept at room temperature for 1 or 2 hours : 0·4 c. c. of each mixture was then
injected subdurally into a rabbit.
For each observation control experiments with salt solution instead of serum were
made, that is to say, mixtures consisting of equal quantities of salt solution and the
emulsions of different strengths were prepared, kept under the same conditions and for
the same time as the serum mixtures, and 0·4 c. c. of each mixture injected subdurally
into a rabbit. In some instances also control experiments with normal human serum
were made in the same manner.
In all, six series of observations were made, the results of which are as follows :—
1. TABLE 13.
(a) Ser um of pat i ent af t er 9 days' t r eat ment .
(b)Serum of pat i ent aft er 14 days' t reat ment .
(c)Salt solution.
In each case the blood was drawn 24 hours after the inoculation.
The mixtures were left for two hours at room temperature.
Dilution of emulsion.
Result of inoculation into rabbit.
(a)
(b)
(c)
1 in 50. .
7 days*
7 days
7 d a y s *
14 ,,
13 ,,
14
,,
1 in 150 . . .
7
,,
7
,,
17 ,,
14 ,,
15
,,
21 ,,
1 in 500. . .
Recovered
Recovered
Recovered
1 in 1,500 . . .
Do.
11 days
Do.
17 ,,
* N. B.—In this and the succeeding tables the upper figure refers to the period of incubation of the
disease after subdural inoculation of 0·4 c. c. of the mixture into a rabbit, the lower figures
to the interval between injection and death.