230 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [III, III.

general experience that in the following year or years " animals once affected with
the disease are almost certain to have it recur " (Kerr, 1829) at the same seat or
in sites far away, where there have been no wounds, to the exclusion of other
animals, indicate that the mechanism underlying the production of natural cases
of the disease is not so simple as the current fly-transmission theory would imply.
The exclusion of other animals is remarkable, since infected flies undoubtedly have
access to all animals housed in a particular stable, where there had been a case or
cases previously. Further, it is known that the prevention of contamination of
wounds from infected flies and the local application of numerous otherwise very
efficient drugs, have failed in the hands of many workers to prevent the recrudes-
cence of the sores in certain parts several years in successions, or of fresh sores
in other parts of an effected subject; but the available information shows that the
larvae in the skin lesions soon die out, i.e., within a month of implication. Again,
that bursati sores persist during the whole of the special season, which is several
times longer than one month, is known. The control and cure of Bursati should
have been achieved by now by the prevention of reinfection by bandaging or appli-
cation of fly-repellents, like Van Saceghem's [1918] Plaster of Paris and Naphthalene
preparation, if the fly theory represented a true picture of the essential pathogenic
process; but the unfortunate fact that Bursati is still incurable, recurrence is
common and destruction of affected cases is still practised, shows that fly trans-
mission is not the usual method. The work of Margarinos Torres [1924] however
proves that occasionally the migration of larva, deposited in a superficial wound,
may take place.

The possibility of infection taking place through the general circulation, which
has already been suggested by Laulanie [1884] in the case of Summer Sores, offers an
interesting alternative, following naturally as a corollary to the significant histo-
pathological findings, referred to above. That the clinical peculiarities of Bursati
are such that one cannot resist the belief that the disease is more than a mere local
infection has already been stated and a consideration of expressions, such as, a
" bursati diathesis " [Collins, 1874], " peculiar conditions of the patient's system "
[Smith, 1879], " constitutional predisposition of the disease " ["Max ", 1876] used
by several workers, makes it obvious that a certain subjective factor is indispensable
to the production of the sores. The subjective factor or " bursati diathesis " would
seem to resolve itself into the infestation of the equine stomach through the inter-
mediary agency of flies and the consequent floating of the migratory worm larvae in
the general circulation. Some of the earliest observations, such as " the poison
appears to be carried to other parts of the body " [Meyrick, 1878] would point to the
intervention of the general circulation, and the same is again supported by the com-