The Scarlet Trail (1918)

Bob Grafton and Ethel Harding fall in love and become engaged, but when a newspaper story reveals that the boy's father Ezra made his fortune by selling bogus patent medicines for the treatment of venereal diseases, the girl's father forbids the marriage. Having learned from his father that the accusations are true, Bob angrily leaves home, whereupon his father confronts the reformer who exposed his activities. When bribery fails, he and his allies launch a campaign to ruin the reformer's reputation by alleging that her sexual hygiene program constitutes a moral threat to children. Meanwhile, the young man, accompanied by his sweetheart, visits his army enlistment office, where he learns from the medical examiner that he has inherited an incurable blood disease from his father. Realizing that he can never marry, Bob returns home, writes his father a scathing letter and shoots himself.