THE ETIOLOGY OF BURSATI.                           223

Apart from the local lesions, there is scarcely any systemic disturbance, and
bursati does not impair an animal much from its serviceable qualities unless the
disease has assumed a very extensive form, or has affected the penis, the seat of
saddle or the angle of the mouth. The disease generally occurs in old animals but
young animals are also affected. As a rule, there is only a single case in a stable,
and the disease has not been observed to spread by direct or indirect contagion to
other equine subjects, housed in the same or in an adjoining stable. Removal
of a diseased animal, in the height of the Bursati season, to particular places, e.g.,
Jhansi, or to the hills, has been observed by more than one worker [ Burke, 1881,
Holmes, 1914 ] to exercise a very salutary effect on the course of the disease. It is
said that cases of Bursati are not so frequent now-a-days as compared with what
they were a generation ago, and this may probably be explained as being due partly
to the better hygienic conditions now obtainable for our animals, and partly to a
diminution of the number of horses in the country.

                                  PATHOLOGICAL HISTOLOGY.

Unlike other aspects of Bursati, its pathological histology has been dealt with
by remarkably few workers. Even in Holmes' description, superseding as it does
the earlier and more imperfect attempts, a consideration of it has been dismissed
in about twenty lines. Credit, however, is due to him for having described for the
first time certain essential features of Bursati, e.g., the presence of a marked eosi-
nophile infiltration and what he terms, empty spaces of varying sizes. From the
foregoing remarks it is clear that a fuller and, at the same time, a more correct
description of the histological features of these growths is certainly indicated at this
juncture. Again, for the successful elucidation of further problems regarding the
mode of infection and efficient methods of diagnosis and control, the definite and
significant histological findings recorded below, should serve as helpful indications.

Materials for the present studies were provided by a valuable collection of 26
samples of preserved growths, received at this Institute from time to time since 1922
to date, from different parts of India. Of these a few were neoplastic or merely
inflammatory in nature; and although some samples were in a bad state of preserva-
tion it is satisfactory to record that the same helminthic incitant was consistently
demonstrated in 17 samples, obtained from such distant parts as Assam, United
Provinces, Hyderabad-Deccan, the Punjab and North-West Frontier Province.
Further, in these positive cases and in 5 other samples from the same collection
typical microscopic lesions, which in the light of present experience may be consi-
dered as of more value in diagnosis than even the worm larvae, have been persis-