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INFLUENCE OF SOLAR RADIATION ON IMMUNITY, II [Vol. XXI, Part III,
immunized hill-bulls of the 1st experiment lived, and perhaps, this wide difference
of environmental temperature under which two experiments were carried out might
be responsible for the difference in the rate of release of the antibody in the circulation.
Besides the factors enumerated above, which apparently exert their detri-
mental influence on the production of antibodies when the animal is exposed to the
sun, thyroid and parathyroid secretions and certain biochemical changes in the
tissues also play an important role in this process. The chief action of thyroid
secretion is on the basal metabolism, i.e., on the general itssue system, and the
parathyroid secretion, in conjunction with vitamin D, helps the assimilation of
minerals, chiefly Ca and P. These secretions are increased when the animal is in
a cooler environment and are diminished when the animal is in a hotter environment.
Therefore, the beneficial functions of these secretions are diminished in the 'Sun
group' animals during the period of the antibody formation, whereas, they are
enhanced in the 'Shade group' animals during the same period. This alone explains
the important role of these secretions in the general body resistance to the infectious
diseases. With a view to study this phenomenon in the experimental animals,
some of the blood constituents, e.g.,—Hb, R.B.C., C.V., Ca., P and Mg were esti-
mated in both the groups once before vaccination and again after the reaction period.
Efforts were also made to find out the co-relation, if any, between these constituents
and the formation of antibodies. Statistical analysis of the results of the estima-
tions revealed that in the 'Sun group',—Hb per cent, R.B.C. Count and total cell
volume were considerably decreased after the reaction period, whereas in the 'Shade
group',—the corresponding decrease was less marked. As regards the calcium and
inorganic phosphorus contents of the blood before vaccination and after reaction
period, much useful information was available. On the whole, these two con-
stituents were decreased in varying extents in the 'Sun group' after the reaction
period, but in the 'Shade group' they were found to be either almost same or
increased in variable extents after the reaction period. There was practically not
much change in the magnesium content of the blood in both the groups before
vaccination and after the reaction period. The decrease in the blood constituents
of the 'Sun group' after the reaction period could be co-related with the lower
potency of the immune serum. Similarly, comparatively higher level of the blood
constituents of the 'Shade group' after the reaction period could be co-related with
the higher potency of the immune serum.
The biochemical changes due to the exposure to solar radiation include the
destructive action of ultra-violet radiation on such components as proteins and
nucleic acids of living cells which are altered to produce some other products. En-
zymes are also subject to alterations by the radiation.
The systemic effects
include the release of histamine-like dilator substances. There might be certain
other changes going on in the tissues due to the exposure to the solar radiation, but
nothing is known so far regarding these activities. The biochemical changes,
referred to above, particularly the destructive action of the ultra-violet on the living
cells, may, perhaps, be indirectly linked up with the decreased formation of anti-
bodies in the 'Sun group' animals.
In the series of experiments with goat tissue vaccine on different species. of
animals, it has been found that in all the experiments, the severity of the reaction
in the 'Sun group' animals was much more pronounced than that in the 'Shade