There would be ninety-nine journeys of two cats each, and one cat over.
'I almost think we might keep the one cat over,' said Anthea.

'I don't seem to care for cats just now, but I daresay I shall again some day.' And she fell asleep.

Jane also was sleeping.
It was Jane who awoke with a start, to find Anthea still asleep.

As, in the act of awakening, she kicked her sister, she wondered idly why they should have gone to bed in their boots; but the next moment she remembered where they were.
There was a sound of muffled, shuffled feet on the stairs.

Like the heroine of the classic poem, Jane 'thought it was the boys', and as she felt quite wide awake, and not nearly so tired as before, she crept gently from Anthea's side and followed the footsteps.