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of the disease. The distribution of this malady seems to be entirely influenced by the physical aspect
of the country. It appears to be chiefly brought about by the occurrence of floods and inundations,
being far more prevalent in those parts of the country where these occur than in the higher and drier
portions. It is far more common in the vicinity of the rivers and canals than in portions of the
country where water is scarce. It is not usual for the natives of India to make any provision for the
maintenance of their animals in the form of hay or dried grass. The usual custom is either to graze
their cattle where grass is to be found, or to cut it from the jungles and wastes as it is required.
Towards the end of the hot season grass on the higher lands has become burnt up ; at lower levels,
especially at the bottoms of nálas, swamps, and ponds, where water has been lying till a much later
period, an abundant supply can generally be found, and it is from these sources that it is procured.
Similar conditions operate at intervals during the wet season, or directly the rains have ceased,
especially in those parts of this country where the temperature is high at this time of the year. The
lands bordering on rivers and streams, or those which are low-lying, become flooded, the herbage is
covered with water, which, in some cases, when the land has a clayey sub-soil, disappears almost
entirely by gradual evaporation, and such places are favourable for the development of low forms of
life, and possibly for the Trypanosoma. Animals, therefore, which daily consume grass and drink
water from such localities run a risk of taking into their systems the contagium of this disease. In
confirmation of these statements we may mention one example from many collected. The inhabitants
of a village "Naoni" in the Ghaziabad Tahsil of the Meerut District, visited by Veterinary-Captain
Pease in 1895, informed him that some forty out of sixty camels attacked had died out of a herd
of 250. The people now drive the camels away to the Bangar or higher lying grounds during the
rains, and water those animals which remain in the lowlands from wells only, in order to escape the
disease. They attribute the disease to stagnant water, and do not allow their camels to drink at open
places until the water has stood for a considerable time and become "pakka" (wholesome). On the
other hand, Veterinary Captain G. H. Evans* reported the case of a pony which contracted Surra in
a compound in Rangoon ; the grass was obtained by its attendant from any source available, while
the water supplied to the animal came from the municipal supply pipes. This was the first case of
Surra acquired in that city observed by the above officer during a residence of some 6 or 7 years.
(III).—The bite of certain species of Flies.
It has been generally surmised from time immemorial that flies may be the carriers of the con-
tagium of different diseases, but it was not until travellers in different parts of the world recorded
individual instances that special attention was directed to these reports. In 1886, Livingstone brought
forward evidence of the terrible losses to animals in Central Africa, the effects of the bite of the
Glossina morsitans, and later Kay-Lees, in 1888, produced similar evidence of losses sustained to
Government Transport animals in the Naga hills. But in both these instances microscopical proof
was wanting. In 1891, Lingard demonstrated microscopically that the body fluids of certain flies,
after sucking the blood of Surra animals, contained the Trypanosoma in varying numbers; and further
that healthy animals inoculated with such soiled material, after a period of incubation, contracted the
disease. In 1895, Bruce re-produced the Nagana disease in equines by taking them down to the fly-
country and allowing them to be bitten by the 'Glossina morsitans' but taking special care that the
animals under experiment did not graze or drink water during the visit of some hours' duration to that
locality.
From the above evidence, therefore, it is quite certain that some species of flies are capable of
carrying the virus, and if their mouth and piercing organs are soiled with blood from infected animals,
their bite may be the means of re-producing the disease in the animals bitten. The great point of
interest, however, lies in the question whether flies can take in the ' Trypanosoma,' when drinking
water, &c., from the swamps and jungles, their natural habitat, and produce the disease by their bite
in healthy animals, in the absence of a previous case of Surra. This problem remains to be settled, and
until it can be proved that the organism in question has been demonstrated on the proboscis, or in
body fluids of flies, in which no extraneous blood is present at the time of examination, the problem
will remain unsolved. The question is a difficult one, and will take much time and careful investigation,
but is one of special interest.
Limited outbreaks have been investigated in this country, where little or no evidence to help in
the elucidation of the cause of the outbreak was forthcoming, and after exceedingly careful examination
of the pros and cons, it, was impossible to form any conclusion as to why 6 out of 8 horses belonging
to one European owner out of a total of 70, the others belonging to natives, should succumb to Surra,
when all the animals were stabled within 200 yards of each other on the slope of a hill, 3,000 feet
elevation, and when the animals attacked were the only ones which were subjected to proper attention
and supervision. The solution of such a problem would necessitate that an observer should remain
at the locality for some months and that careful microscopical observations of the body fluids of all
species of flies caught on the animals be made daily from the end of the hot season until after the ap-
pearance of the disease, between July and November, for the onset of the epizootic varies year by year
according to the rainfall of the locality.
* Annual Report—Imperial Bacteriologist, 1896-97, page 20.