‘I asked to see Don Andres de Fonseca,’ she said in a low quick voice.  ‘You are not he, senor.’

‘Andres de Fonseca was buried to-day,’ I answered.  ’I was his assistant in his business and am his heir.  If I can serve you in any way I am at your disposal.’

‘You are young—­very young,’ she murmured confusedly, ’and the matter is terrible and urgent.  How can I trust you?’

‘It is for you to judge, senora.’

She thought a while, then drew off her cloak, displaying the robes of a nun.

‘Listen,’ she said.  ’I must do many a penance for this night’s work, and very hardly have I won leave to come hither upon an errand of mercy.  Now I cannot go back empty-handed, so I must trust you.  But first swear by thine blessed Mother of God that you will not betray me.’

‘I give you my word,’ I answered; ’if that is not enough, let us end this talk.’

‘Do not be angry with me,’ she pleaded; ’I have not left my convent walls for many years and I am distraught with grief.  I seek a poison of the deadliest.  I will pay well for it.’

‘I am not the tool of murderers,’ I answered.  ’For what purpose do you wish the poison?’

’Oh!  I must tell you—­yet how can I?  In our convent there dies to-night a woman young and fair, almost a girl indeed, who has broken the vows she took.  She dies to-night with her babe—­thus, oh God, thus! by being built alive into the foundations of the house she has disgraced.  It is the judgment that has been passed upon her, judgment without forgiveness or reprieve.  I am the abbess of this convent—­ask not its name or mine—­and I love this sinner as though she were my daughter.  I have obtained this much of mercy for her because of my faithful services to the church and by secret influence, that when I give her the cup of water before the work is done, I may mix poison with it and touch the lips of the babe with poison, so that their end is swift.  I may do this and yet have no sin upon my soul.  I have my pardon under seal.  Help me then to be an innocent murderess, and to save this sinner from her last agonies on earth.’

I cannot set down the feelings with which I listened to this tale of horror, for words could not carry them.  I stood aghast seeking an answer, and a dreadful thought entered my mind.

‘Is this woman named Isabella de Siguenza?’ I asked.

‘That name was hers in the world,’ she answered, ’though how you know it I cannot guess.’

’We know many things in this house, mother.  Say now, can this Isabella be saved by money or by interest?’

’It is impossible; her sentence has been confirmed by the Tribunal of Mercy.  She must die and within two hours.  Will you not give the poison?’

’I cannot give it unless I know its purpose, mother.  This may be a barren tale, and the medicine might be used in such a fashion that I should fall beneath the law.  At one price only can I give it, and it is that I am there to see it used.’