So they waited under the trees until the sun had gone in and the birds were all asleep in their nests, and then the fox climbed stealthily into the trees and gathered the birds one after the other, just like a naughty schoolboy stealing apples from a farmer's orchard.
Having obtained what she required, the Princess set forth eagerly to carry the remedy to the Prince's palace.
But the fox, who had taken care to keep well out of her reach, suddenly sat down and began to laugh.
'Why do you laugh, dear fox?' asked the Princess. 'Is it that you are overjoyed to think that the Prince who is to be my husband will soon be restored to health? But let us hurry: we may be too late!'
'No, it is not that,' said the fox, laughing again. 'It is to think that your remedy will be of no avail without the other ingredient, which is the blood of a fox, and as I am not minded to supply it, I will skip the reward you promised and be off.'
Thereupon he started away, pelting as hard as he could go.
The Princess saw that her only hope was to outwit the fox, and she immediately thought of a plan to gain her end.
'Dear fox, do not run,' she said; 'that would be a pity now that the remedy is in our own hands. The King is certain to reward us lavishly, and surely there are plenty of other foxes among whom we can find one willing to spare his blood to save the King's son. Let us go on, then, and trust to our fortune.'
The fox, proud of the fact of being the most artful animal alive, never thought for one moment that he could be exceeded in cunning by a simple maiden, so he came back to the Princess, and together they walked through the forest to the far end where the palace of the King showed in the near distance.
'That is the place,' said the fox; 'but we haven't got the other ingredient!'