The “dangerous tendency” rule and explained “If the words uttered create a dangerous tendency which the state has a right to prevent, then such words are punishable. It is not necessary that some definite or immediate acts of force, violence, or unlawfulness be advocated. It is sufficient that such acts be advocated in general terms. Nor is it necessary that the language used be reasonably calculated to incite persons to acts of force, violence, or unlawfulness. It is sufficient if the natural tendency and probable effect of the utterance be to bring about the substantive evil which the legislative body seeks to prevent.