y 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.'

She thought a while and answered: 'It may be done, for as it chances the
wording of my absolution will cover it. But you must come cowled as a
pr