6:30
`` The worst man in London , '' Holmes answered , as he sat down and stretched his legs before the fire . `` Is anything on the back of the card ? '' I turned it over . `` Will call at 6:30 -- C.A.M. , '' I read . `` Hum ! He 's about due . Do you feel a creeping , shrinking sensation , Watson , when you stand before the serpents in the Zoo , and see the slithery , gliding , venomous creatures , with their deadly eyes and wicked , flattened faces ?