September, 1951]
AMRITAMOY
MUKHERJI
167
group' animals. This might be attributed to the probable detrimental influence
of the solar radiation on the first-line defence mechanism in the exposed animals.
The antigen, instead of being subjected to the activity of the local tissue cells, e.g.,
histiocytes, reticular cells, etc., pass on unchecked to the blood circulation and sub-
sequently to the liver, spleen and other tissues and give rise to much pronounced
reactions. Whereas in the 'Shade group', probably due to the cooler atmospheric
temperature in which the animals lived, the first-line of defence is more active and
the antigen is acted upon by the glandular and regional tissue cells and then allowed
to pass on to the circulation, thus giving rise to milder reactions as compared with
the 'Sun group'. The severity of the reaction, however, bears no relationship to
the concentration of antibodies in the circulation as a result of immunization.
The effect of solar radiation on the incubation period of rinderpest was observed
and was found that in case of both the experiments on hill-bulls, the incubation
period in the 'Sun group' was less than that in the ' Shade group', but in case of
the other two experiments with buffaloes and goats, the incubation period in both
the groups was the same. Thus, no conclusion can be drawn with regard to this
unless more number of experiments are conducted under sun and shade.
A comparison of the body weight of both the groups before vaccination and
after the reaction period revealed that the 'Sun group' animals suffered more loss
of body weight after the reaction period than the 'Shade group' animals. The
highly significant decrease in the body weight of the 'Sun group' animals after the
reaction period in all the four experiments on rinderpest was directly due to the
severity of the reactions, which again was primarily attributed to the detrimental
influence of solar radiation on the exposed animals.
A comparison between the mortality figures among the reactors of both the
groups during the reaction and convalescent periods revealed that more number
of deaths occurred among the 'Sun group reactors'.
Lastly, the influence of solar radiation on the resulting immunity was studied
in all the four experiments on rinderpest and very interesting results were obtained.
The immunity test was done in all the experiments three months after vaccination.
In the first exepriemnt with hill-bulls, where the percentage of potency of immune
serum of the 'Sun group' was found to be 8.2 as against 42.2 of the 'Shade group'
the immunity test revealed that half the number of the animals belonging to the
'Sun group' were partially immune, while the remaining animals of the 'Sun
group' and all the animals of the 'Shade group' were found to be immune. This
partial breakdown of immunity in some of the animals of the 'Sun group' might
be attributed to the initial low concentration of antibodies in the immune serum as
revealed by the potency test. In the subsequent experiment with hill-bulls, the
percentage of potency of immune sera of both the groups was found to be zero.
The immunity test revealed that only 2 hill-bulls of the 'Shade group' were still
immune and out of the remaining 6 hill-bulls, 3 died of rinderpest due to complete
breakdown of the conferred immunity and 3 suffered from rinderpest but recovered
thus indicating a partial breakdown of immunity at the end of three months after
vaccination. Out of 7 hill-bulls of the 'Sun group', 4 died of rinderpest and 3 were
found to be partially immune as they suffered from rinderpest but recovered. The
breakdown of immunity, partial or complete three months after vaccination, was
evidently due to the very poor quality of serum as proved by the potency test.