F. C. MINETT
101
light local reaction. Tests showed that meat-
er cultures of Cl. welchii and Cl. septicum
re fatal in the above conditions to Cl. chauvoei-
mune guinea-pigs.
croscopical
With anthrax and blackquarter, in order to
ck the cultural results, films (standard loopful
er one sq. cm. surface) and sections of similar
ckness were prepared and stained by methylene
e for direct counting from tissues of animals
mediately after death and again after the lapse
some hours. With blackquarter the films were
m bone marrow (guinea-pigs) and the sections
in liver (guinea-pigs and sheep). With anthrax,
ne marrow films were unsuitable but satisfactory
ults were obtained with films from the heart-
od of mice, taken first from one side of the heart
then from the other. Between the first and
ond examination, the carcase was stitched up.
1. Past. septica
The strain in use was given to me by Mr V. R.
jagopalan, and had been isolated from a bovine
mal in 1939. By storage on blood agar under
paraffin, it had retained a high virulence for the
rabbit, 1.0 c.c. 24-hour broth culture at dilution
of 10 -4 subcutaneously killing 14-23 hours later.
Death would occur with great suddenness, animals
apparently well except for a little dullness, would
fall on their sides, scream and die after a few
struggles. The average number of Pasteurella
colonies, developing from 1.0 c.c. bone-marrow
suspension at dilution of 10 -5 or 10 -6 at various
times after death is shown in Table I. The
unopened carcases were stored in a room at tem-
perature maintained between 60 and 70°F.
The results indicate that within six hours after
death the organism multiplies in the bone marrow.
The count then remains stationary up to 48
hours or so, after which the numbers usually start
to decline. They are still numerous, however,
and in pure culture in the marrow as. long as eight
days after death. At the period of maximal
growth the mean number of living organisms per
gm. bone marrow for 15 rabbits was 2181
millions (range 306-6840, S.D. 1866). In a buffalo
calf dying less than 24 hours after inoculation with
Pasteurella the count was 1467 millions per gm.
of marrow.
TABLE I
Past. septica in rabbit carcases
Hours after death
. . 0 . . .
. . 6 . . .
. . 8 . . .
. . 9 . . .
. . 18 . . .
. . 24 . . .
. . 33 . . .
. . 46 . . .
. .57 . . .
. . 81 . . .
. . 129 . . .
. . 168 . . .
. . 192 . . .
. . 194 . . .
Rabbit number
1
2
3
4
5
6
Average colony count from 1.0 c.c. 10 -5
47
397
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
27
1,209
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
22
312
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
466
1,307
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
581
. .
. .
. .
. .
. .
. .
6
. .
. .
. .
. .
. .
. .
364
. .
. .
. .
. .
. .
. .
. .
133
. .
7
8
9
10
11
12
13
14
15
Average colony count from 1.0 c.c. 10 -5
. .
. .
485
. .
. .
537
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
1,063
. .
. .
1,056
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
263
. .
. .
. .
. .
165
. .
. .
. .
. .
. .
. .
. .
. .
190
. .
. .
. .
. .
217
. .
. .
. .
. .
. .
. .
. .
. .
. .
328
. .
. .
202
. .
. .
. .
. .
. .
. .
. .
. .
. .
. .
134
. .
. .
. .
. .
127
. .
. .
. .
. .
. .
. .
. .
. .
253
. .
. .
. .
. .
. .
90
. .
. .
. .
. .
. .
. .
. .
472
. .
. .
. .
. .
. .
. .
110
. .
. .
. .
. .
. .
. .
759
. .
. .
. .
. .
. .
. .
. .
. .
. .
198