Friday night about half past 8 o'clock, John SPEARS saw a man go down to South Market Wharf (St. John) in a manner which excited his suspicion so strongly that, although he allowed him to pass, followed him immediately in hope of preventing evil. The man, however, reached the end of the wharf before he could overtake him, jumped off and has not been seen since. Mr. SPEARS at once gave the alarm. It is supposed that the suicide was Laurane KEEGAN who left his house in Smith's Alley about that time. His description answers that of Keegan whose cap was found next day in the slip. Keegan was a drunken and worthless character and his wife has been in the Penitentiary. - Freeman