midnight
` And , I say , Mr Jules , if Mr and Mrs Sampson Levi , or any other Hebrews or Christians , should again invite you to my hotel you will oblige me by declining the invitation . You 'll find that will be the safest course for you . ' ` Good night , sir . ' Before midnight struck Theodore Racksole had ascertained that the invitation-list of Mr and Mrs Sampson Levi , though a somewhat lengthy one , contained no reference to any such person as Jules . He sat up very late . To be precise , he sat up all night . He was a man who , by dint of training , could comfortably dispense with sleep when he felt so inclined , or when circumstances made such a course advisable .