IMMUNITY IN CALVES AGAINST RINDERPEST             133

protection. The virus was obtained from Kumaon hill-bulls, artificially infected,
and in those cases which showed no evidence of reaction at the normal period
(fourth or fifth day) after inoculation, a further dose of virus was administered.
In all cases the virulence of the virus used for immunisation and for testing the
duration of immunity was tested by inoculation into susceptible hill-bulls.

      Altogether 128 calves have so far been used for this experiment, of which the
records of 98 (30 of indigenous breed and 68 indigenous X European) are given in
the appended Table I. The remainder either died, were destroyed for other
experimental purposes, or were otherwise disposed of before the period of test.

                                                                                                                                        B 2