171
The left ventricle is contracted. The muscular tissue of the wall measures at its greatest width 1.8 inches and its
cavity is almost empty. The internal surface presents numerous sub-endocardial extravasations, somewhat extensive in
certain situations, especially involving the tissues lying behind the posterior segment of the mitral valve and the upper por-
tions of the musculi-papillares, and there are smaller ones studded over the muscular surface of the cavity. The valves are
healthy.
The abdominal cavity contains a few ounces of a turbid, orange fluid.
The Liver is small and dark in colour. It weighs 7 lbs 6½ ozs. The convex surface of both lobes shows signs of old
perihepatitis. On section, the tissue is dark in colour, and dark fluid blood exudes from the cut ends of the vessels.
The Spleen is normal in size ; the surfaces are studded with numerous brick-red sub-capsular petechiæ, which present
an almost confluent appearance at the free borders. On section, the tissues present a dark purple-red colour. Follicles
normal in size.
The Kidneys.— Right weighs 1 lb. 1 oz. ; Left 1 lb. Capsules thin and easily separable ; surfaces are smooth, and of
a dark-red colour. The tissues on section are dark. The malphigian corpuscles are very prominent ; but there is no other
change.
The Stomach is large and somewhat distended. It contains a considerable amount of semi-digested grass. The cuti¬
cular portion presents a fairly healthy condition, the only change noticeable being a small area of a pale pink colour. The
mucous membrane of the villous portion is thin and there is a strip of a pale-red colour, 1.5" in width, which extends along
the line of demarcation. About midway between the cuticular border and the pyloric opening, there is an irregular shaped
patch, measuring 3" × 2", the surface of which is covered with ragged mucous membrane, from which it has become
detached, and nearer to the pylorus the surface of the organ is somewhat granulated. A few single spiroptera are scattered
over the surface of the villous portion.
The small Intestine presents a few small patches, upon which the vessels are injected and present an arborescent appear¬
ance, the surrounding tissues for a short distance being blood-stained. There are also two or three small, dark, raised
tumours, somewhat circular in form and ¼th of an inch in diameter, which on section of the mucous membrane covering them
are found to be formed by small clots of blood lying on the middle coat of the intestine.
The Large Intestine contains pultaceous, greenish-brown, semi-fluid masses, as far as the Colon—in this portion, con-
sistent, and formed dung. The Cæcum presents a patch 1" × 5", bright red in colour, caused by extravasated blood beneath
the mucous membrane. No parasites were found in the intestines although carefully searched for.
The bladder contains a few ounces of a turbid, very viscid, orange coloured fluid, Sp. Gr. 1,036, acid in reaction. The
internal surface of the organ presents a healthy appearance.
Remarks.—This experiment was undertaken in order to test the efficacy or otherwise of the excrement of the Rat (Mus
Decumanus) as a means of producing " Surra" by gastric ingestion. For this purpose, numerous rats were obtained, the
blood of each being submitted to careful microscopical examination, and those animals in which the hæmatozoon was found to
be present were placed in an iron wire-cage by themselves. "When a sufficient number of these latter was obtained.
the cage was placed over a metal plate, and the excrement which fell through was collected in the morning and mixed with
corn, and so given to the animal subjected to experiment, at 8 A.M. and 6 P.M.
Every week the blood of the caged rats was again submitted to microscopical examination, and those in which the
hæmatozoon was found to be absent were discarded, and their places filled by fresh ones in which the organisms were found
to be numerous.
The experiment was commenced on the morning of the 26th November 1892, and was continued until the evening of
the 7th February 1893—a period of seventy-four days. Small doses (grammes iii) were given at first, but these were varied
later according to the quantity of excrement obtainable. During the whole course of the case the temperature never exceeded
38.1° C. except on two occasions. One might be inclined to consider the negative result in this case as clear evidence of the
innocuous properties of rat-dung, and its inability to produce Surra. But before doing so, there are three points which will
have to be taken into consideration.
1. The fact that Surra is not enzootic in Poona or on the Deccan plateau, probably on account of the dryness of the
situation ; and it was recognised therefore before commencing the experiment that the result might prove negative.
2. It is a well ascertained fact, and the statistics in the Surra Report, Volume I, furnish the proof, that in Bombay
the deaths from Surra as a rule commence in September, and new cases practically cease at the end of December. Conse-
quently this experiment was undertaken at too late a period of the year, and any future experiment in this line should be
commenced if it can be arranged in Bombay, or at all events below the gháts, towards the end of the hot weather, and
continued during the rains. The latent period in the case of experimental inoculation by gastric ingestion of small quantities
of blood, known to contain the hæmatozoon (vide horse No. XX) occupied 130 days from the first, and 75 days from the
final exhibition of the soiled blood, until the appearance of the hæmatozoon in the general circulation. Consequently, if we
consider it probable that the cause of the outbreak at the Bombay Tramway Company's Stables was due to the horses
consuming rat-excrement in their corn, and we take as an instance the outbreak of 1892, when three horses were attacked
with Surra on the 12th and 14th of September ; these animals must have commenced the ingestion of the grain soiled with
the damp excrement, about July 1st, 1892, according to the shorter, or on the 6th May 1892, according to the longer
computation. The grain we must suppose is contaminated during the whole year, but certain changes in the rat excrement
take place at different seasons—the most important being dryness after the rains in October, November and December, which
is still more accentuated during the hot weather but at the commencement of the rains the dung becomes soft, and remains
so, thus allowing the lower forms of life present in it to be developed.
3. A third point which has been noticed in cases submitted to inoculation with rat's blood is, that the hæmatozoon of
rats (kept for any time in captivity, and fed on clean corn) appears to lose in virulence. The positive cases which have been
recorded in horses in this report were inoculated with blood taken from rats which had been caught only a few hours
previous to their blood being used for the purpose of inoculation. Some species of rats are very clean feeders, but the Mus
Decumanus of this country is not so, and eats any food which is procurable ; where no grain is obtainable it having recourse
to offal or fæcal matter.