What tone could be used for best effect for this line from the passage?
"There isn't any, no there's not!"

Question

What tone could be used for best effect for this line from the passage? 
  "There isn't any, no there's not!"

anonymous · Answer

Like whooping cough, from child to child, 
 He sped to spread the rumor wild: 
 "Sure as my name is Jabez Dawes 
 There isn't any Santa Claus!" 
 Slunk like a weasel or a marten 
 Through nursery and kindergarten, 
 Whispering low to every tot, 
 "There isn't any, no there's not!"

 The children wept all Christmas Eve 
 And Jabez chortled up his sleeve. 
 No infant dared to hang up his stocking
 For fear of Jabez' ribald mocking. 
 (from The Boy Who Laughed At Santa Claus by Ogden Nash)