The following constitute no defence to an action for slander and libel:

That the defendant believed the charges that were made, to be true.75

That the charges were made under the influence of sudden passion.76

That there had been a prior publication of the libel by a third person.77

That there were reports and rumors previously existing.78

The bad character of the plaintiff is not a complete defence;79 but may be shown in mitigation of damages.80