RINDERPEST.                             127

of Plains breed. The serum prepared in these experiments
by the exclusive use of Plains buffaloes is equal in potency to
serum derived from the exclusive use of cattle of Hill breed.
Consequently, Plains buffaloes can be to a large extent used in
the place of Hill cattle. They are cheap, and can be obtained
in sufficient number, also few die during the process of bleeding
and serum preparation.

     Owners do not object to selling buffaloes for Laboratory
purposes. By the mixture of serum prepared by this method
from Plains buffaloes with the serum prepared in like manner
from Plains bulls, I consider that brews of Rinderpest anti-
serum can be manufactured of a potency equal to that of the
Muktesar serum. A serum of good practical value can be pre-
pared from Plains bulls by a single massive injection of viru-
lent blood obtained from Plains bull controls. The virulent
blood is diluted in an equal volume of Pot. Cit. solution and
is injected at a negative phase, namely, during the actual period
of an attack of Rinderpest or immediately after.

     The serum prepared from Plains cattle is not so potent
as that from Plains buffaloes. It is, however, as strong as
that obtained from Plains cattle injected with virus from Hill
bulls by our present routine method. The Plains cattle used
for this experiment were inexpensive animals of ordinary vil-
lage type. They were only slightly susceptible to Rinderpest
and few died during the process of serum preparation. In all
these experiments the bleedings for serum were made at a period
of about fourteen days following the massive injection. The
satisfactory results show that the anti-bodies are present at
that time.

     Under our present routine a period of three weeks at least
is allowed from last injection. In further operations this pe-
riod can be curtailed to two weeks.

     If the practical application of these methods meets with
the same success in the routine serum making preparation at
Muktesar, a large number of Plains buffaloes can be used to
supply virus and a lesser number of Hill bulls will be required.