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C.—Organs of Digestion.
1. The Pharynx and Œsophagus rarely present any abnormal appearance,
but if any are present in the latter, they are usually small wounds in the epithe-
lium, due to the presence of the " Spiroptera scutata."
2. The Stomach.—Some previous observers* have described the presence
of ulcers in the stomachs of mules and horses, which have succumbed to this
disease. Steele noted in the Burmah outbreak, that out of twelve cases certain-
ly affected with Surra, nine had ulcers in the stomach; but at a later date, he
found that animals of the same species, which died from other causes than
'Surra,' likewise presented the same pathological lesions. Evans states "that
he examined with great care in every case in which he had an opportunity, the
kidneys, liver, spleen, heart, lungs, and the mucous lining of the stomach and
intestines throughout, and he is prepared to state positively, that this disease
is not characterized by any structural organic change."
Again, Gunn remarks in his report on the post-mortems of three grass-cut-
ters' ponies, which succumbed to Surra:—" The villous portion in these cases
remained unaffected. In no case was ulceration to be seen, but the cuticular
portion of the stomach was much thickened, and on the internal surface were
observed numerous papillary eminences, each having a small and somewhat deep
central depression."
In this investigation, in the majority of cases the cuticular portion of the
stomach has practically been found free from grave complications.
In one case, No. I, the cuticular portion of the organ was described as
thickened, but inexperience at that early period of the research probably led one
to overlook the fact, that the coats were merely contracted. A. partial yellow
colouration of the lining membranes, either only involving the left sac, or in
others staining both sides of the line of demarcation, was noted in one naturally
acquired case of the disease (Horse No. II), and in five inoculated cases (Horses
Nos. V, XX, XXX, XIX, XXXIV); and congestion of the cuticular portion was
found once (Horse No. XXIV).
The villous portion or the right sac was much more frequently found to be
the seat of marked changes.
Ulcers occurred in two cases, Horses XIX, XL, and were probably due to
the effects of parasites. Congestion only in fourteen—three in naturally
contracted cases (Horses Nos. I, III, LXV)- nine in inoculated animals from
horse to horse (Nos. V,VI1, XI, XV, XIX, XXI, XXII, XXXII), and two
through the goat (Horses Nos. XL, XXXI).
Petechias in one naturally acquired (No. II), and in three inoculated (Nos.
XI, XV, XXII). In one inoculated case extravasations of blood were present
(No, VI), abd small, round, elevated white patches in one naturally contracted
case, viz. (No. LXXI). With regard to parasitical tumours, due to the presence
of large numbers of the Spiroptera Megastoma, they were present in three natu-
rally acquired cases (Nos. III, LVI, LXX), whilst in inoculated cases from horse
to horse they were observed in XXIII, and from goat to horse, &c., in two
(Nos. LX, L) ; and in case No. XXXIII, an extravasation of blood had occurred
beneath the mucous and muscular coats.
3. The Small Intestines.—In a number of cases no pathological change of
any kind is observable. On the other hand it is by no means infrequent to find
the mucous membrane between the duodenum and the cæcum, more or less in-
jected in patches, and ecchymoses dotted about either singly or in small groups.
The solitary glands and Peyers's patches are never found enlarged or ulcerated,
but the former present a pale colour, whilst in the latter, the slightly pigmented
condition of health.
In those cases we have examined the small number
of entozoa present in the small intestines have been particularly noticeable, and
especially has this been the case in Australians. Of the naturally acquired
cases, two presented patches of congestion (Nos. II, LXV), and one (No. XL)
in those horses inoculated from the goat.
* Steele, Shaw, and Frost—(Burmah outbreak).
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