On reaching home the previous night, all her other sensations had been absorbed in a vague feeling of mingled dread and curiosity, produced by the sight of the weird figure in the yellow mask, which she had left standing alone with Fabio in the palace corridor.  The morning light, however, suggested new thoughts.  She now opened the note which the young nobleman had pressed into her hand, and read over and over again the hurried pencil lines scrawled on the paper.  Could there be any harm, any forgetfulness of her own duty, in using the key inclosed in the note, and keeping her appointment in the Ascoli gardens at ten o’clock?  Surely not—­surely the last sentence he had written, “Believe in my truth and honor, Nanina, for I believe implicitly in yours,” was enough to satisfy her this time that she could not be doing wrong in listening for once to the pleading of her own heart.  And besides, there in her lap lay the key of the wicket-gate.  It was absolutely necessary to use that, if only for the purpose of giving it back safely into the hand of its owner.

As this last thought was passing through her mind, and plausibly overcoming any faint doubts and difficulties which she might still have left, she was startled by a sudden knocking at the street door; and, looking out of the window immediately, saw a man in livery standing in the street, anxiously peering up at the house to see if his knocking had aroused anybody.

“Does Marta Angrisani, the sick-nurse, live here?” inquired the man, as soon as Nanina showed herself at the window.

“Yes,” she answered.  “Must I call her up?  Is there some person ill?”

“Call her up directly,” said the servant; “she is wanted at the Ascoli Palace.  My master, Count Fabio—­”

Nanina waited to hear no more.  She flew to the room in which the sick-nurse slept, and awoke her, almost roughly, in an instant.

“He is ill!” she cried, breathlessly.  “Oh, make haste, make haste!  He is ill, and he has sent for you!”

Marta inquired who had sent for her, and on being informed, promised to lose no time.  Nanina ran downstairs to tell the servant that the sick-nurse was getting on her clothes.  The man’s serious expression, when she came close to him, terrified her.  All her usual self-distrust vanished; and she entreated him, without attempting to conceal her anxiety, to tell her particularly what his master’s illness was, and how it had affected him so suddenly after the ball.

“I know nothing about it,” answered the man, noticing Nanina’s manner as she put her question, with some surprise, “except that my master was brought home by two gentlemen, friends of his, about a couple of hours ago, in a very sad state; half out of his mind, as it seemed to me.  I gathered from what was said that he had got a dreadful shock from seeing some woman take off her mask, and show her face to him at the ball.  How that could be I don’t in the least understand; but I know that when the doctor was sent for, he looked very serious, and talked about fearing brain-fever.”