27
As at Karnal so at this depôt the maximum number of cases of Filaria Oculi, viz., eight
(8) in 1895 occurred after a season of heavy rainfall amounting to 60.34 inches. But, on the
other hand, five cases were observed in the cold season of 1897, with only 27.74 inches during
the water-famine year; and one case only was operated upon in 1893, when 47.49 inches of
rain fell. Consequently it would appear that a warm humid atmosphere is most advantageous
to the development of the parasite.
For the information of readers non-resident in India, it must be noted that by far the
greater part of the rainfall of this country is brought by the summer-monsoon over a great
part of Western India, including nearly the whole of the Bombay Presidency. It is only
during this season, viz., June to October, that there is any rain of importance. This is the
chief season of rainfall in Burmah, Assam, Bengal, North-Western Provinces, greater part of
the Punjab, Central India, Rajputana, and the Central Provinces, Hyderabad, the Deccan,
Berar, Guzerat and the whole of the west coast of the Peninsula. But the south-east of the
Peninsula, including the Carnatic and the Eastern Ghats and the eastern half of Ceylon,
receive only an occasional shower, so long as the main body of the monsoon is directed towards
Northern and Central India, and their season of heaviest rainfall comes later, viz., from Oc-
tober to December, when north-east winds are beginning to blow in the north-west of the
Bay. As the heaviest rainfall occurs in the Madras district during the last quarter of the
year, one would expect that the Filaria Oculi would make its appearance during January to
May in each year, and this is what does happen.
Length of time stationed in the locality before
being affected with Falaria Oculi.
On reference to the above table, it will be observed that of the twenty-one horses affected
with " worm in the eye" which occurred at
Saharanpur Depôt between the years 1893 to
1897, inclusive, 14 or 66.6 per cent. were Austra-
lians and 7 or 3.33 per cent., Country-Breds. The average period which elapsed between
the date of purchase and admission to hospital for Filaria Oculi varied in the case of the
former animals between one and three years, or a mean of eighteen months and six days each.
As the date of birth of the country-bred animals is not forthcoming, it is impossible to
draw any deductions with regard to the period which elapsed between birth and the appear-
ance of the parasite.
As far as I am aware only two helminthologists have described the microscopical appear-
ances of the Filaræ extracted from the anterior chamber of the eye of the horse. Davaine,
who received his specimens from the Madras Presidency, gives them the following characters :—
" Body capillary, reddish white or chestnut in colour, and a little expanded towards the
first quarter of its length ; integument smooth, mouth provided with three salient, triangular
lips ; tail acute, with two long and strong papillæ at the sides, a little in advance of the end
and directed backwards. Male : Λ 30 mm. to 35 mm. long, tail spiral and having between
the two caudal papillæ, six papillæ on each side, three pre-anal and three post-anal; two short
spiculæ, with an accessory piece. Female: Λ 22 mm. to 32 mm. long, genital tube still
destitute of ova."
Neumann in 1896, examined a number of specimens forwarded to him by Spooner-Hart
of Calcutta and summarized his conclusions as follows :—
" The body is whitish or of a red tint, thread-like, elongated, narrowed towards either
extremity, especially towards the tail. Integument is not transversely striated, but a faint
longitudinal marking is evident. The mouth is small round guarded by two lateral lips, semi
lunar in outline, united (very often) in the median line above and below by projecting papillæ,
which are of less diameter at the base than at their free extremities. At the summit of each
papillæ is a blunt shallow depression, the rim surrounding the depression having two notches
in it. (Esophagus is short, narrow, not bulbous at all, and with a capillary lumen. The large
intestine is straight, from an eighth to a fifth the length of the body, and filled with brownish
contents. The rectum is slightly sinuous, almost empty and colourless. The anus is situated
from 130 to 160 μ from the tip of the tail in the male ; in the female it is from 300 to 350 Μ
from the caudal extremity, and just in front of its termination are two papillæ, lateral in
position, conical in shape, with summits directed backwards.
Special characters of the Male.
Average length 33 mm. varying between 16 to 42 mm. ; width from 250 to 300 μ
The tail is coiled into an open spiral, and provided with seven papillæ on either side.
Three of these papillæ are pre-anal in position, whilst one is found bordering the anus laterally,
the prominent papillæ are sub-terminal. Two spicules of unequal length, one being 85 μ the
other 220 μ are also present; they are always retracted.
Female.
Average length varying between 28 and 43 mm. ; from 300 to 500 μ thick. The
tail is curved somewhat, with the concavity upwards. Ovaries have no distinct eggs. The
vulva is situated 90,100 or 110 μ from the cephalic end of the worm. "
This observer concludes that the worm is a young form of the Filaria Equina which in
the adult condition may be found in the peritoneum, and maintains that any differences