NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
E. O. LONGLEY 151
Results.—In one case only, of the seven goats used, were there pulmonary
lesions. This goat, No. 42, was placed in contact with the second consign-
ment of goats received from the field on the 8th of December 1938. It re-
mained in contact for the rest of the month with the addition of two further
consignments during that period, and died on the 1st of January 1939.
Throughout, no temperature was present, but a cough developed from the
21st of December 1938 (at the 13th day of contact). At post mortem, con-
solidation of the diaphragmatic lobes of left lung with congestion of the left
costal pleura, was found. No larvae of Oestrus ovis were present in this parti-
cular case. Owing to the natural death of this animal, no transmission ex-
periments from the lesions could be attempted. Its fellow goat, No. 43, was
destroyed by reason of extreme debility from helminthic infestation on the
20th of December 1938. No pulmonary lesions were present at post mortem
The histories of these and the remaining five goats are condensed in the follow-
ing table.
TABLE XVI
Goat No.
42
43
64
65
66
69
70
Date of
admission to
contact
3 December 1938
Do.
29 December 1938.
Do.
5 January 1939
2 February 1939
Do.
Date of death
1 January 1939
20 December 1938
28 January 1939
10 January 1939
2 February 1939
21 February 1939
8 February 1939
Period of
contact
in days
24
12
30
12
28
19
6
Lungs at autopsy
Pleuro-pneumonia
present.
No lesions
No lesions
Do.
Do.
No lesions
Do.
Cause of death
Pneumonia.
Destruction.
Debility.
Do.
Do.
Test inoculation.
Debility.
Goat No. 69 received, on the 17th of February 1939, after 15 days con-
tact, an intra-muscular inoculation of 10 c. c. of a virulent pneumonic lung
emulsion, and died with a local reaction, four days later.
It will be seen from the above, that contact varied from 6 to 30 days,
but in no other instance than that mentioned did pulmonary lesions develop,
death resulting from debility, generally associated with inter-current cocci-
diosis or helminthiasis.
(b) Experiment 17. Transmission by contact with experimental cases
It was decided to attempt a second experiment on this issue, which is
important both in practice and experimentally, and of considerable interest.
Accordingly five goats in good condition were placed on the 2nd of June
1939 in contact, i.e. in the same loose box of size 20 ft. x 20 ft., as in the
previous experiments, with five goats which had been insufflated on the
23rd of May 1939 with pneumonic lung emulsion ex the 8th passage of strain
152
Contagious Pleuro-pneumonia of Goats
42/46. Over the ensuing six weeks these five goats were continuously
maintained in similar contact with three further reacting groups, the details
of which are tabulated below.
TABLE XVII
' Donors ' at contact
Contact
No.
1st in-contact {
2 June 1939.
2nd contact {
11 June 1939.
3rd contact {
22 June 1939.
4 th contact {
29 June 1939.
Goat
No.
256
257
258
259
260
261
262
263
264
265
266
267
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
42/46 Strain
Passage
9th passage
Do.
Do.
Do.
Do.
10th passage
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
First 11th passage
Do.
Do.
Do.
Do.
Second 11th pass-
age.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Inoculation
date
23 May 1939
Do.
Do.
Do.
Do.
2 June 1939
Do.
Do.
Do.
Do.
Do.
Do.
6 June 1939
Do.
Do.
13 June 1939
Do.
Do.
Do.
Do.
22 June 1939
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Pulmonary lesions at
death on
+ + + + 3 June 1939
+ + + + 7 June 1939
+ + + + 6 June 1939
+ + + + 2 June 1939
—
4 July 1939
+ + + + 13 June 1939
—
22 June 1939
+ + + +
Do.
+ + + + 15 June 1939
—
22 June 1939
+ + + + 11 June 1939
+ + + + 15 June 1939
—
22 June 1939
+ + + +
Do.
+ + + + 19 June 1939
+ +
29 June 1939
—
Do.
+ + + +
Do.
+ + + +
Do.
—
Do.
+ + + + 11 July 1939
+ + + + 4 July 1939
+ + + + 6 July 1939
+ + + + 11 July 1939
+ + + +
Do.
+ + + + 8 July 1939
+ + + + 7 July 1939
+ + + + 6 July 1939
+ + + + 4 July 1939
+ + + + 11 July 1939
Period
of
contact
in days
1
5
4
6 hours.
22
2
11
11
4
11
...
4
11
11
8
7
7
7
7
7
12
5
7
12
12
9
8
7
5
12
It will be seen that this procedure involved contact with as many as 30
goats, 24 of which were positive cases at autopsy. The actual periods of
E. O. LONGLEY 153
contact with individual reactors varied from six hours (just prior to death)
to 12 days, and thus covered the entire course of the infection (at this time
very acute) many times over, and all stages of the disease. On the 13th of
July 1939, at the conclusion of the total six weeks of contact, all the five
goats received inoculations of virulent pneumonic lung emulsion, as a test of
their susceptibility. The results are shown below.
TABLE XVIII
Goat
No.
268
269
270
271
272
Test
Date
13 July 1939
Do.
Do.
Do.
Do.
Route
and dose
S/C 5 c. c.
„
„
„
„
Material
}P. L. E. in Tyrode'a
(1:1) ex goat 387.
Result
Local
lesion
+ + + +
+ + + +
+ + + +
+ + + +
+ + + +
Lung
—
—
—
—
—
Remarks
Died on 18 July
1939.
Died on 20 July
1939.
Died on 18 July
1939.
Do. .
Do. .
Survival
days
p. ins.
5
7
5
5
5
All the five reacted fully, and fatally, four dying at the fifth, the remain-
ing one at the seventh day p. i. All reactions were typical and very severe.
Neither pulmonary nor pleuritic lesions were present at autopsy in any of
the five goats.
Summary.—(1) Only one of a total of 12 goats placed in close contact
with natural and experimental cases of pneumonia for periods up to six weeks
developed the disease.
(2) All the 6 of the 12 goats tested for immunity by the inoculation of
pneumonic lung emulsion were found to be fully susceptible.
C. Miscellaneous
(1) a. Experiment 18. Viability of the infective agent tested by inoculation
With a view to making a preliminary examination of the viability of the
agent in cold storage, the two portions, one in saline, the other glycerinated,
of the virulent pneumonic lung emulsion ex donor No. 16 used in Experi-
ment 4 and stored at 0°—5°C., were taken on the 21st of December 1938,
after 48 hours storage, and administered each to two healthy goats as below:
TABLE XIX
Inoculum
Untreated emulsion . . . . .
Glycerinated emulsion
.
.
.
.
Goat No.
56
57
58
59
I/M
5 c. c.
„
„
„
S/C
5 c. c.
„
„
„
Result .
—
—
—
154
Contagious Pleuro-pneumonia of Goats
Results.—As shown, no significant reactions resulted in any of the four
recipients, and neither systemic nor febrile disturbance was evident. As
previously recorded, this material when fresh had infected five of six suscepti-
ble goats.
Experiment 19—
As work with an agent as fragile as the preceding experiment indicated
was clearly to be a difficult and very uncertain matter, it was decided to
arrange at the earliest possible opportunity a more complete test of the powers
of rasistence of the agent.
Procedure.—Accordingly, three portions of the mixed effusion and lung
juice, prepared by the usual technique from donor goat No. 34, destroyed on
the 4th of February 1939 with excellent and typical pulmonary lesions and
which proved to be a most virulent emulsion, were bottled and placed in the
cold store at 0°—5°C. as follows :—
(a) with the addition of an equal volume of saline (pH. 7.4),
(b) with the addition of an equal volume of sterile glycerine,
(c) with an equal volume of Tyrode's solution (pH. 7.4).
The scheme of the experiment was to inject the saline emulsion intra-
muscularly in 5 c. c. doses into pairs of goats at 48 hours intervals until attenua-
tion was evident, and then to switch to the Tyrode and glycerine mixtures,
giving the same doses. The details of the inoculations and the results are
given in Table XX.
Two controls were inoculated with the fresh emulsion to control its
primary virulence. Both developed typical progressive local lesions with
natural death 4 days p. ins.
TABLE XX
Goat No.
Date of injection
Storage
Result
(Local
lesions)
Remarks
Survival
days
p. ins.
1. With saline
73
78
94
95
98
99
104
105
4 February 1939
„
6 February 1939
„
8 February 1939
..
10 February 1939
„
0 hours
„
48 hours
„
90 hours
„
144 hours
„
+ + + +
+ + + +
+ + + +
+ + + +
+ + +
+ + +
+ +
+ +
Died on 8 February 1939
Do.
Died on 13 February 1939
Destroyed in extremis on
12 February 1939.
Receded by 20 February 1939
Receded by 15 February 1939
Slight reactions only, receding
by 15 February 1939.
3
3
7
5
E. O. LONGLEY 155
TABLE XX—contd.
Goat No. Date of injection.
Storage
Result
(Local
lesions)
Remarks
Survival
days
p. ins.
2. With glycerine
106
107
116
117
142*
11 February 1939
„
13 February 1939
„
18 February 1939
170 hours
216 hours
336 hours
+ + +
+ + + +
+ +
+
+
Receded by 20 February 1939
Died on 17 February 1939
Slight reactions receding by 17
February 1939.
......
Slight reaction receding by 23
February 1939.
...
6
...
...
...
3. With Tyrode
108
109
118
119
143
144
11 February 1939
„
13 February 1939
„
18 February 1939
„
170 hours
„
216 hours
„
336 hours
„
+ + +
+ + + +
+ + +
+ + +
+ +
+ +
Receded by 21 February 1939 .
Died on 16 February 1939 . .
Receded by 20 February 1939 .
......
Slight reaction receding by 25
February 1939.
......
...
5
...
...
...
...
Results.—It will be seen that the emulsion alone was lethal at 48 hours
but not at 96 hours. The injections of the Tyrode and glycerine mixtures
were commenced at the 170th hour (7 days), when each proved lethal in one
goat only. 48 hours later (at the 9th day) neither proved fatal on injection,
though a moderately severe reaction resulted in both recipients of the Tyrode
mixture.
(1) b. Experiment 20.—Viability of the infective agent tested by insufflation
It was considered important to re-examine this issue with the insuffla-
tion technique, and also to determine the viability at room temperature,
particularly as a knowledge of this would have a bearing on the despatch of
material to the laboratory. It was decided to test by insufflation, the viabi-
lity of the virus at room temperature up to 48 hours, and in cold storage at
7 and 14 days.
Procedure.— The donor (goat No. 387) slaughtered on the 13th of July
1939,14 days p. i. had excellent early lesions and considerable pleuritic effusion.
Emulsion (1:1 Tyrode's) was prepared as usual, a portion separated for
storage and the residue administered by intra-nasal insufflation to ten control
goats, five of whom received 10 c. c. of the neat emulsion, and the other
five, 1 c. c. of emulsion in 9 c. c. of Tyrode's solution. The results are
shown in Table XXI below.
* One goat only available.
E
156
Contagious Pleuro-Pneumonia of Goats
TABLE XXI
Primary virulence controls
Goat No.
461
462
463
464
465
466
467
468
469
470
Date of insufflation
13 July 1939.
„
„
„
„
„
„
„
„
„
Material
P. L. E. ex goat
387.
I c. c. I/Nas.
„
„
„
„
10 c. c. I/Nas.
„
„
„
„
Result
(Lungs)
+ + + +
+ + + +
+ + + +
+ + + +
—
+ + + +
+ + + +
+ + + +
—
+ + + +
Remarks
Destroyed on 27 July 1939
Do.
Destroyed on 28 July 1939
Died on 25 July 1939
Destroyed on 28 July 1939
Do.
Destroyed on 27 July 1939
Destroyed on 28 July 1939
Do.
Do.
Survival
days
p. ins.
14
14
15
12
15
15
14
15
15
15
The main emulsion (1 : 1) was split into two equal portions. To one was
added an equal volume of Tyrode's solution, and to the other an equal volume
of sterile glycerine. Half of each such preparation was placed in cold storage
(0°—5°C.) and the other half retained at room temperature (90°—95°F.).
Each preparation was administered to groups of four goats on the lines
discussed in the introduction and with the following results .
TABLE XXII
At room temperature
A. In Tyrode's solution
Goat No.
471
472
473
474
479
480
481
482
Date of insufflation
14 July 1939.
Do.
Do.
Do.
15 July 1939.
Do.
Do.
Do.
Period of
storage
24 hours
Do.
Do.
Do.
48 hours
Do.
Do.
Do.
Result
(Lungs)
—
—
+ + + +
—
—
—
—
—
Remarks
Destroyed on 9 August 1939
Do.
Died on 5 August 1939
Destroyed on 9 August 1939
Destroyed on 9 August 1939
Do.
Do.
Do.
Survival
days
p. ins.
26
26
22
26
25
25
25
25
E. O. LONGLEY 157
B. In glycerine
Goat No.
475
476
477
478
483
484
485
486
Date of insufflation
14 July 1939
Do.
Do.
Do.
15 July 1939
Do.
Do.
Do.
Period of
storage
24 hours
Do.
Do.
Do.
48 hours
Do.
Do.
Do.
Result
(Lungs)
—
—
—
—
—
+ + + +
—
—
Remarks
Destroyed on 9 August 1939
Do.
Do.
Do.
Destroyed on 9 August 1939
Do.
Do.
Do.
Survival
days
p. ins.
26
26
26
26
25
25
25
25
In cold storage
A.—In Tyrodes solution
Goat
No.
498
499
500
501
536
537
538
539
Date of insufflation
20 July 1939
Do.
Do.
Do.
27 July 1939
Do.
Do.
Do.
Period
of
storage
7 days
Do.
Do.
Do.
14 days
Do.
Do.
Do.
Result
(Lungs)
+ + + +
+ + + +
—
—
—
—
—
—
Remarks
Died on 2 August 1939
Destroyed on 9 August 1939
Destroyed on 12 August 1939
Do.
Destroyed on 17 August 1939 .
Do.
Do.
Do.
Survival
days
p. ins.
13
20
23
23
21
21
21
21
B.—In glycerine
Goat
No.
502
503
504
505
540
541
542
643
Date of insufflation
20 July 1939
Do.
Do.
Do.
27 July 1939
Do.
Do.
Do.
Period,
of
storage
7 days
Do.
Do.
Do.
14 days
Do.
Do.
Do.
Result
(Lungs)
—
—
—
+ + + +
—
—
—
—
Remarks
Destroyed on 12 August 1939
Do.
Do.
Do.
Destroyed on 17 August 1939
Do.
Do.
Do.
Survival
days
P. ins.
23
23
23
23
21
21
21
21
158
Contagious Pleuro-pneumonia of Goats
Results.—The fresh emulsion had infected eight of ten controls, and half of
these in 1/5th the test dose used in the main experiment, and all by the 15th
day p. ins.
It will be seen that after 24 hours at room temperature, the Tyrode pre-
paration infected one of its four recipients, the glycerinated preparation none.
At 48 hours, the Tyrode infected none and the glycerinated one only. After
seven days cold storage, two of the four animals receiving the Tyrode prepara-
tion and one of the four receiving the glycerinated preparation were infected.
After 14 days cold storage, neither preparation was infective.
Summary.—(1) In a preliminary experiment, material that was infective
when fresh to five of six goats, failed to infect after cold storage, both as a
saline emulsion and with the addition of glycerine any of the four experiment-
ally inoculated goats.
(2) In a second experiment, the organism in pneumonic lung emulsion
in cold storage retained a lethal degree of virulence at inoculation as follows :
(a) In saline, at 48 but not 96 hours.
(b) In Tyrodes solution, at seven but not at nine days.
(c) In 50 per cent glycerine, at seven but not nine days.
(3) A pneumonic lung emulsion that infected eight out of 10 goats when
fresh, was tested by insufflation, and retained its infectivity as follows :
A. At room temperature (90°—95°F.):
(i) In Tyrodes solution, in one of four goats at 24 hours, in none of
four goats at 48 hours.
(ii) In glycerine, in none of four goats at 24 hours, in one of four
goats at 48 hours.
B. In cold storage (0°—5°C.):
(i) In Tyrode's solution, in two of four goats at seven days, in none
of four goats at 14 days.
(ii) In glycerine, in one of four goats at seven days, in none of four
goats at 14 days.
Discussion.—It is evident from these results that the etiological agent
possesses very poor powers of resistance. In saline in cold storage, it could
not retain its virulence for four days, in one instance not even for 48 hours.
And neither Tyrode's solution nor glycerine, both of which appear to be similar
in effect, could maintain its infectivity in cold storage for more than seven
days. The prolonging of its infectivity with the addition of glycerine is,
however, noteworthy. After 24 hours storage at room temperature, it in-
fected only one of eight goats, as compared with eight of ten when fresh.
The results at both inoculation and insufflation are quite congruous, and
explain the failure of previous attempts at transmitting the disease, using
materials collected in the field and despatched by post or rail to laboratories,
and demonstrates the virtual hopelessness of inaugurating any passage in
laboratories with such material. It also justifies our practice of using only
materials collected and prepared on the day of the experiments.
2. Experiment 21.—Susceptibility of other species to infection by inoculation
The purpose of this experiment was to determine the susceptibility of
buffaloes, bovines, and sheep, to intra-muscular inoculation.
E. O. LONGLEY 159
Donors.—The two donors were Nos. 42 and 46, received from the field,
the originators of the experimentally maintained strain, intra-pulmonary
passage of which proceeded from the day following the present experiment.
Procedure.—Emulsion was prepared in the usual way with the addition
of what effusion was present, and injected immediately to the subjects and in
the doses shown below.
TABLE XXIII.
Species
Bovine
(bullocks)
Buffalo
(calves)
Sheep
(ewes)
Goat (con-
trols)
No.
1
2
1
2
1
2
120
121
122
123
Date
14 February
1939. Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Do.
Body
weight
250 kilos
162 kilos
61 kilos
95 kilos
...
...
...
...
...
...
Route
I/M
„
I/M
„
I/M
„
I/M
„
„
„
Dose
75 c. c.
„
20 c. c.
„
20 c. c.
„
5 c. c.
Do.
2.5 c.c
Do.
Results reaction
local
Lameness, tender-
ness and slight
swelling at 24
hours : reaction
pletely at 72
hours.
+ + + +
+ + + +
+ + +
+ + + +
+ + + +
+ + + +
Remarks
...
...
...
Died on 18 Feb-
ruary 1939.
Died on 19 Feb-
ruary 1939.
Reaction receded
by 25 February
1939.
Died on 19 Feb-
ruary 1939.
Destroyed
21
February 1939.
Destroyed
23
February 1939.
Survival
days
p. ins.
...
...
...
4
5
...
5
6
8
As already detailed in Experiment 8, two more goats received this inoculum
' supra-costally ' and both died with extensive local lesions. Cultural and
biological tests of the inoculum were made as usual, with negative results.
Results.—Slight lameness, tenderness and swelling on the following day
were present in both the bovines and buffaloes. Very little reaction was
present at 48 hours, and none at 72 hours. The reaction appeared to be a
non-specific effect of the massive particulate inocula. In both the ewes very
severe fatal œdema resulted. The lesions at autopsy were the same as in the
goat species.
All the four control goats reacted fully, one case dying at the 5th day p. i.,
two being destroyed in extremis at the 6th and 8th days, p. i., the other surviv-
ing and making a slow recovery.
Experiment 22.—Confirmation of the susceptibility of sheep to inoculation
An experiment to confirm the susceptibility of the sheep species, this
time to the inoculation of muscle effusion alone, as opposed to P. L. E., was
undertaken on the 6th of March 1939.
Donor.—Muscle effusion from goat No. 177, destroyed on the 6th of March
1939 with a severe local reaction (Experiment 12), was injected in 10 c.c. doses
160
Contagious Pleuro-Pneumonia of Goats
intramuscularly into six ewes. Two healthy control goats received the same
dose by the same route. Two guinea-pigs and two rabbits were injected
intramuscularly with 1.5 c. c. and 2.5 c. c. of effusion respectively, without
effect.
The details and the results are tabulated below :
TABLE XXIV
Animal
Ewe . .
Goat . .
No.
3
4
5
6
7
8
196
197
Date
6 March 1939
„
„
„
„
„
Do. .
„
Inoculum
Muscle effusion
ex goat No. 177.
10 c. c. 1/M
.
„
„
„
„
„
Do. .
„
Results
+ + + +
+ + + +
+ + + +
+ + + +
+ +
+ + + +
+ + + +
+ + + +
Remarks
Died on 11 March 1939
Died on 12 March 1939
Died on 11 March 1939
Died on 13 March 1939
Destroyed on 15 March 1939
Died on 11 March 1939
Destroyed on 11 March 1939
Died on 11 March 1939
Survival
days
p. ins.
5
6
5
7
9
5
5
5
Results.—As shown above, all animals except ewe No. 7 reacted fully and
typically. Very marked lesions were present as in the previous experiment.
Experiment 23.—The susceptibility of ewes to infection by the intra-nasal route.
Donors.—Two goats slaughtered on the 27th of April 1939, reactors at
the 5th intra-pulmonary passage of strain 42/46, provided pneumonic lung
emulsion for the experiment.
Procedure.—The fresh emulsion was administered to five healthy ewes
intra-nasally, by the usual technique, in 12 c. c. doses. Two control groups
were employed. A group of five healthy ewes received the same dose by the
same route of the emulsion after subjecting it to heat at 55°—60°C for 45
minutes, these controlling the effect of the operation ; and five healthy goats
received the fresh emulsion, these controlling its infectivity. The results are
shown below.
TABLE XXV
Susceptibility of ewes to intra-nasal insufflation
Animal
Ewe
No.
14
15
16
17
18
Date
27 April 1939.
„
„
„
„
Material
Fresh P. L. E.
ex goats 209
and 212.
„
„
„
„
Route
and
dose
12 c. c.
I/Nasal.
„
„
„
„
Result
(Lungs)
—
—
—
—
—
Remarks
Died on 12 June 1939
Destroyed on 19 June
1939.
Died on 13 May 1939
Died on 14 June 1939
Died on 11 June 1939
Survival
days
p. ins.
46
53
16
48
45
E. O. LONGLEY
161
Animal
Ewe
Goat
No.
9
10
11
12
13
226
227
228
229
230
Date
27 April 1939
„
„
„
„
Do.
„
„
„
„
Material
Fresh P. L. E.
ex goats 209
and 212.
heated to 65°—
60°C. for 46
minutes.
„
„
„
„
Fresh P. L. E.
as above.
„
„
„
„
Route
and
dose
12 c. c.
1/Nasal.
„
„
„
„
12 c. c.
1/Nasal.
„
„
„
„
Result
(Lungs)
—
—
—
—
++++
—
++++
++++
++++
Remarks
Died on 4 May 1939
Destroyed on 19 June
1939.
Do.
Died on 15 May 1939
Destroyed on 19 June
1939.
Died on 9 May 1939
Destroyed on 20 June
1939.
Died on 9 May 1939
Died on 11 May 1939
Destroyed on 10 May
1939.
Survival
days
p. ins.
7
53
53
18
53
12
54
12
14
13
As shown, four of the five control goats developed the pneumonia, with
deaths in three instances at the 12th to 14th days p. ins. All lesions were
typical and severe. The remaining goat slaughtered on the 20th of June 1939,
54 days p. ins., had no pulmonary lesions at autopsy.
Of the experimental group of ewes, one died at the 16th day from natural
causes. The remainder survived for periods varying from 45 to 53 days. All
were entirely free from pulmonary lesions at autopsy, as also were those of the
control group.
Susceptibility of small laboratory animals
As stated earlier, all inoculations in goats have been controlled by inocula-
tions in guinea-pigs, sometimes rabbits, and rarely in mice. A total of 98
guinea-pigs, 50 rabbits, and eight mice has been used, and in no instance has
any specific reaction been observed.
Summary.—(1) None of the two bullocks and two buffaloes inoculated
intra-muscularly with weight-proportionate doses of a pneumonic lung emul-
sion that caused full lesions in three of four control goats, developed signifi-
cant lesions.
(2) Two ewes inoculated with the same material died four and five days
p. i. respectively, with full local reactions.
(3) In a second experiment, five of six ewes died with full local reactions
at the site of intra-muscular inoculation of effusion from similar local lesions
in goats.
(4) None of five ewes receiving intra-nasal insufflations of a pneumonic-
lung emulsion that infected four of five control goats developed any pulmonary
lesions.
(5) None of five ewes receiving the same preparation heated at 55°—60°C.
for 45 minutes developed any pneumonia.
(6) No evidence of susceptibility to inoculation was adduced in a total of
98 guinea-pigs, 50 rabbits, and eight mice inoculated.