cclviii
RATS.
RATS (MUS DECUMANUS) INOCULATED WITH HORSE-SURRA BLOOD.
Experiment I.—December 5th, 1890.—A rat was placed in a separate cage and its
blood carefully examined in order to find out whether it was free from the hæmatozoon.
Daily examinations were conducted with this end in view until December 19th, but
always with negative results. Consequently on that day at 1P.M., the rat was inoculated
subcutaneously with .2 c.c. of blood containing very numerous hæmatozoa, taken from the
Jugular Vein of Horse No. VII.
20th December.-
21st
22nd
23rd
24th
25th
26th
„
„
..
„
„
„
-The blood
„
„
„
„
„
„
contained a few hæmatozoa.
„
a few
„
„
very numerous hæmatozoa.
„ „ „ „
„ „ „ „
was swarming with very numerous hæmatozoa.
contained countless swarms of hæmatozoa. Death took place
at noon.
AUTOPSY.—The
body is well nourished, and on an examination of it being made, all
the organs presented a healthy appearance, with the exception of the spleen, which was very
much increased in size, of a dark-red colour, firm to the touch, and weighed two grammes.
Remarks.—The blood of this animal was submitted to careful microscopical examination
for a period of fourteen days, and as the hæmatozoon was not observed in it, subcutaneous
inoculation was made with .2c.c. of blood containing very numerous hæmatozoa from the horse.
On the next day a few organisms were found in the blood, which, in the course of a few days,
increased to very numerous and swarming. The rat died on the seventh day after inoculation
with its blood teeming with hæmatozoa. The chief points of interest in this case are :—
(i). The shortness of the period of incubation, viz., one day only.
(ii). The exceedingly short time which elapsed between the appearance of the
organism in the blood and death, clearly emphasizing the virulence of Surra-
blood, when taken from the horse and injected into the rat (Mus decumanus).
Experiment II.—December 22nd, 1890.—Obtained three rats (Mus decumanus), two of
which were full grown, and the third a young one about two months old. On careful
microscopical examination of the blood of each animal no hæmatozoa could be discovered.
23rd December.—After a second careful examination of the blood of each animal with
negative results, the full grown rats Nos. I and II were subcutaneously inoculated, each
receiving .1c.c. of blood containing a few hæmatozoa, taken from the Internal Jugular Vein
of horse No. VII. The small rat No.III was not inoculated, but was placed in the cage with
Nos. I and II to act as a control experiment.
Date.
December, 24th...
„
25th...
26th
27th...
„
28th...
29th...
30th...
31st...
January, 1st 1891.
Rat No. I.
Hæmatozoa absent from the
blood
„ few in the blood
...
„. few
„ numerous in the blood ...
„ very numerous „
„ very numerous „
„ very numerous „
Found dead at 6
A.M.
...
Rat No. II.
Hæmatozoa absent from the
blood
„ few in the blood
„ numerous
„
„ very numerous „
„ very numerous „
„ swarming
„
„ swarming
„
Found dead at 6 A.M
...
Rat No. III.
Hæmatozoa absent from the
blood.
„ absent
„ absent
„ few
„ few
„ numerous
„ very numerous
„ swarming
Found dead at 5 A.M.
„
„
„
„
„
AUTOPSY.
No. I.—All the organs are healthy with the exception of the spleen, which is very much
enlarged and presents numerous, small, raised extravasations of blood which are lying
on the surface of the tissues underneath the capsule.
No. II.—The Lungs are the seat of localized emphysema, but there are no ecchymoses
on the visceral pleuræ. Liver contains several cysts.
Stomach healthy. Spleen very much enlarged and presents numerous, small, raised
extravasations of blood which are lying on the surface of the tissues underneath the
capsule.
No. III.—The Lungs present one round ecchymosed spot, the size of a mustard seed
at the base of the left organ. Heart contains thin watery blood, but no extra-
vasations in the ventricles. Stomach healthy. Liver healthy. The Spleen is very
much enlarged and presents localized patches of extravasation, which have given
rise to elevations on the convex surface, lying under the capsule.