The most reasonable version of the incident, that could anywise be rendered acceptable to the auditors, was substantially the one suggested by the guide of the catacomb, in his allusion to the legend of Memmius.  This man, or demon, or man-demon, was a spy during the persecutions of the early Christians, probably under the Emperor Diocletian, and penetrated into the catacomb of St. Calixtus, with the malignant purpose of tracing out the hiding-places of the refugees.  But, while he stole craftily through those dark corridors, he chanced to come upon a little chapel, where tapers were burning before an altar and a crucifix, and a priest was in the performance of his sacred office.  By divine indulgence, there was a single moment’s grace allowed to Memmius, during which, had he been capable of Christian faith and love, he might have knelt before the cross, and received the holy light into his soul, and so have been blest forever.  But he resisted the sacred impulse.  As soon, therefore, as that one moment had glided by, the light of the consecrated tapers, which represent all truth, bewildered the wretched man with everlasting error, and the blessed cross itself was stamped as a seal upon his heart, so that it should never open to receive conviction.

Thenceforth, this heathen Memmius has haunted the wide and dreary precincts of the catacomb, seeking, as some say, to beguile new victims into his own misery; but, according to other statements, endeavoring to prevail on any unwary visitor to take him by the hand, and guide him out into the daylight.  Should his wiles and entreaties take effect, however, the man-demon would remain only a little while above ground.  He would gratify his fiendish malignity by perpetrating signal mischief on his benefactor, and perhaps bringing some old pestilence or other forgotten and long-buried evil on society; or, possibly, teaching the modern world some decayed and dusty kind of crime, which the antique Romans knew,—­and then would hasten back to the catacomb, which, after so long haunting it, has grown his most congenial home.

Miriam herself, with her chosen friends, the sculptor and the gentle Hilda, often laughed at the monstrous fictions that had gone abroad in reference to her adventure.  Her two confidants (for such they were, on all ordinary subjects) had not failed to ask an explanation of the mystery, since undeniably a mystery there was, and one sufficiently perplexing in itself, without any help from the imaginative faculty.  And, sometimes responding to their inquiries with a melancholy sort of playfulness, Miriam let her fancy run off into wilder fables than any which German ingenuity or Italian superstition had contrived.

For example, with a strange air of seriousness over all her face, only belied by a laughing gleam in her dark eyes, she would aver that the spectre (who had been an artist in his mortal lifetime) had promised to teach her a long-lost, but invaluable secret of old Roman fresco painting.  The knowledge of this process would place Miriam at the head of modern art; the sole condition being agreed upon, that she should return with him into his sightless gloom, after enriching a certain extent of stuccoed wall with the most brilliant and lovely designs.  And what true votary of art would not purchase unrivalled excellence, even at so vast a sacrifice!