12
TABLE IV.
Showing the ratio of spleen weight to body weight, when the hæmatozoon is present or absent
from the circulation of rats [M. d.) male and female, whose body weights are over or
under sixty grammes.
Hæmatozoon
present or absent
in the blood.
Absent
Few
Numorons
Very numerous
Swarming
...
Present
Absent
No.
of
Rats.
186
40
41
47
78
404
218
186
404
Males under
60 grammes
ratio
S toB.W.
1:228.4
1:139.8
1:136.61
1:107.2
1 :125.7
1:228.4
No.
of
Rats.
171
48
32
28
55
334
163
171
334
Females
under
60 grammes
ratio
S to B. W.
1:232.2
1:201.5
1:166.8
1:119.2
1:157.4
1 :232.2
No.
of
Rats.
455
104
37
22
23
611
186
455
641
Males over
60 grammes
StoB.W.
1:205.5
1:190.0
1:154.3
1: 137.9
1:169.1
1:205.5
No.
of
Rats.
578
95
29
23
22
747
169
578
747
Females
over
60 grammes
ratio
S to B. W.
1:203.3
1:144.3
l: 137.4
1:87.5
1:131.2
1:203.3
Ho.
of
Rats.
357
97
76
76
133
738
381
357
738
Males and
Females
under
60 grammes
ratio
S to B. W.
l:230.3
1:166.7
1:147.4
1 :112.0
1: 139.3
1 :230.3
No.
of
Rats.
1,033
199
66
45
45
1,388
355
1,033
1,383
Males and
Females
over
60 grammes
ratio
S to B. W.
1:204.3
1:165.7
1:146.9
1:108.1
1:149.9
1:204.3
5. It will be seen from the above table that the weight of the spleen
increased (from a minimum in the absent cases) in regular gradation, according
to the number of hæmatozoa present in the circulation of the rats.
6. Pregnant.—Of 2,154 rats examined, 1,070 were males and 1,084 females
Seventy-seven females were pregnant, the hæmatozoon being present in the
blood of 19, and absent from it in 58 ; or a percentage of 32.75 as against 67.25.
In no instance has the Trypanosoma been discovered in the circulation of the
fœtus, although at the same time it was present in varying numbers in the blood
of the mother.
7. Parasites (stomach).—Nematode worms, varying in number and di-
mensions, were found in the stomachs of rats: (in some instances the above organ
was fully distended by the number of parasites), in which the hæmatozoon was
either present or absent.
In 2,154 examined during the year, nematodes were found in 23.58 per cent.
But it is of interest to note, that during the rainy season, June to November,
the percentage was 16.27, whilst during the months December to May, it rose to
29.36 per cent. The percentage varied during the twelve months from 7.25 in
July, to 37.50 in April.
8. The great majority of rats present the hæmatozoon in their circulation
some time during the rainy season. From our observations, the spleen attains
its maximum size towards the end of the rains, and from that period the size of
the organ gradually diminishes during the dry and hot season, until the advent
of the following monsoon, unless occasional heavy rain falls between November
and May.
9. It has been observed during the middle of the hot and dry season, that
when rain suddenly falls after a long period of drought (4 months), the percent-
age of animals in which the hæmatozoon is found increases rapidly in the first
few days (7) following the fall.
The percentage then rapidly falls, and a second maximum is reached during
the fourth week.
The increase of percentage in the first week was found to be 7.5, while the
maximum in the fourth week was 11.0 per cent.
B.—Experiments with the Hæmatozoon of the Rat (M. d.).
Horses injected subcutaneonsly on numerous occasions with rat's blood con-
taining swarms of the hæmatozoa, proved refractory to the Rat disease, but
readily contracted Surra in the usual period (5 to 7 days), when a small scratch
on the muzzle was smeared with a trace of soiled Guinea pig blood.