25
on the way up with perforation of the stomach, the result of ulceration, and one at
Nyung Hla Kyoun of " anthrax." On arrival six were sick, but seem to have recovered.
These animals came from an infested locality and seem to have had the disease, and
yet they did not convey it to those at Thayetmyo. On 24th March 1884 four mules
were sent from the depôt to Thayetmyo and two to Tonghoo; in the former place the
disease has not broken out, in the latter it has proved severe, but was commencing
before the arrival of these mules. The depôt ponies which died in the 1883-84 outbreak
arrived from Thayetmyo, a disease-free place, on 19th May 1883. Thus we see that
the prevalence of the disease is not in direct ratio with interchange of animals from
disease centres. This non-contagiousness of the mule disease may be the result of
the organisms not being expelled from the system, but remaining in it until they
induce a fatal result. Whereas in man profuse perspiration occurs as a critical
evacuation in the attacks, no such phenomenon has been observed in the lower animals.
I have not experimented with saliva of mules, which contains organisms a little like
certain forms of spirilla, but have given stomach contents and fluid from the bowels
through the mouth without effect. I thought it possible that the gastric ulcerations and
the circumscribed congestions of the bowels were associated with elimination of parasites
from the system through these organs, but the result has proved negative. Thus
we have strong evidence that the disease is not communicable by contagion or infec-
tion ; we are certain that it may be given by inoculation with, or ingestion of, the blood.
18. Although predisposing causes are subordinate in importance in this disease,
we must give them some attention. Breed and conformation seem to exercise some
influence. Captain Johnstone expresses the non-professional idea on this subject when
he says " the small thick-set mules in general appear to enjoy almost complete immu-
nity." This was noted at Rangoon, where the mules most like donkeys were least
often affected, but, although patent to non-professional observers, this fact has limited
practical value, for not only all sorts of mules, but even ponies of the country, have
succumbed to the Burma disease.
19. With regard to size, it is a matter of constant remark that the larger
mules suffer more from the fever than the smaller ones. This may be due to one or
more of three causes: (a) The big mules are most used and have the hardest work.
(b) Although allowed by Government more food than smaller ones, they, in feeding
off the ground or out of unpartitioned mangers, generally get actually a smaller
amount than their less phlegmatic small companions. Also in the distribution of
gram sufficient care is not always exercised or practicable for securing to each large
mule a large feed. I notice also that, as concerns fodder, the mules are all treated
alike, the allowance for three fellow-workers being placed in front of the three
animals and the sharpest of them obtaining an unduly large share, often, by the
free use of hoofs and teeth, keeping the others away until all the tit-bits are
consumed. It is evident also that, when picketed in the open, large animals will suffer
most, especially they will miss their large ration when it becomes necessary to evenly
distribute insufficient food or to allow animals entirely to shift for themselves. (c)
The influence of breed and conformation may tell here, the largest mules being those
which retain most of the caballine characters of their progenitors, the small ones the
asinine. Although this more frequent attack of large mules has been commented
on especially in connection with their use for puckal work, it certainly cannot be
considered a specially marked feature of the Rangoon outbreak, in which I find 24
mules out of 47 cases were 13 hands and upwards, only 9 of them being 13.2 and
upwards (i.e., first-class mules). In the 3rd Native Infantry at Tonghoo of 57 cases
22 are returned as first-class mules, 32 as second class, and 3 as "not specified."
Thus calculating the percentage of losses on the mules of each class mustered on the
strength, we cannot consider this a marked feature of the disease, although any special
tendency of large mules can be fully explained in the above manner.
20. Age does not seem to influence liability, but vereran mules have succumbed
in considerable numbers. The Tonghoo returns of the 3rd Native Infantry show most
deaths at the ages of 12, 18, and 20, but a fair distribution from 8 years old up to 21
years; however we have already noted the suspicious exactitude of this return as
regards ages. In the Somersetshire Regiment most of the fatal cases were mules of
early adult age, but both old and young also fell victims. Old animals, from the
7