‘You have a marvellous collection of tall stories,’ said Arthur.  ’I’m afraid I should want better proof that these particular snakes are poisonous.’

Oliver turned to the charmer and spoke to him in Arabic.  Then he answered Arthur.

’The man has a horned viper, cerastes is the name under which you gentlemen of science know it, and it is the most deadly of all Egyptian snakes.  It is commonly known as Cleopatra’s Asp, for that is the serpent which was brought in a basket of figs to the paramour of Caesar in order that she might not endure the triumph of Augustus.’

‘What are you going to do?’ asked Susie.

He smiled but did not answer.  He stepped forward to the centre of the tent and fell on his knees.  He uttered Arabic words, which Dr. Porhoet translated to the others.

’O viper, I adjure you, by the great God who is all-powerful, to come forth.  You are but a snake, and God is greater than all snakes.  Obey my call and come.’

A tremor went through the goatskin bag, and in a moment a head was protruded.  A lithe body wriggled out.  It was a snake of light grey colour, and over each eye was a horn.  It lay slightly curled.

‘Do you recognize it?’ said Oliver in a low voice to the doctor.

‘I do.’

The charmer sat motionless, and the woman in the dim background ceased her weird rubbing of the drum.  Haddo seized the snake and opened its mouth.  Immediately it fastened on his hand, and the reptile teeth went deep into his flesh.  Arthur watched him for signs of pain, but he did not wince.  The writhing snake dangled from his hand.  He repeated a sentence in Arabic, and, with the peculiar suddenness of a drop of water falling from a roof, the snake fell to the ground.  The blood flowed freely.  Haddo spat upon the bleeding place three times, muttering words they could not hear, and three times he rubbed the wound with his fingers.  The bleeding stopped.  He stretched out his hand for Arthur to look at.

‘That surely is what a surgeon would call healing by first intention,’ he said.

Burdon was astonished, but he was irritated, too, and would not allow that there was anything strange in the cessation of the flowing blood.

‘You haven’t yet shown that the snake was poisonous.’

‘I have not finished yet,’ smiled Haddo.

He spoke again to the Egyptian, who gave an order to his wife.  Without a word she rose to her feet and from a box took a white rabbit.  She lifted it up by the ears, and it struggled with its four quaint legs.  Haddo put it in front of the horned viper.  Before anyone could have moved, the snake darted forward, and like a flash of lightning struck the rabbit.  The wretched little beast gave a slight scream, a shudder went through it, and it fell dead.

Margaret sprang up with a cry.

‘Oh, how cruel!  How hatefully cruel!’

‘Are you convinced now?’ asked Haddo coolly.