"Which," supplemented Cleek, with one of his curious one-sided smiles, "through an ante-papal union between Pope Alexander VI and the beautiful Giovanna de Catanei--otherwise Vanozza--gave to the world those two arch-poisoners and devils of iniquity, Cæsar and Lucretia Borgia. Lady Essington's family tree supplies a mixture which is certainly unique: a fine, fruity English pie with a rotten apple in it. Hum-m-m! if her ladyship has inherited any of the beauty of her famous ancestress--for in 1490, when she flourished, Giovanna de Catanei was said to be the most beautiful woman in the world--she should be something good to look upon." "She is," replied Narkom. "You'll find her, when she comes, one of the handsomest and most charming women you ever met." "Ah, then she has inherited some of the attractions and accomplishments of her famous forbears. I wonder if there has also come down to her, as well, the formula of those remarkable secret poisons for which Lucretia Borgia and her brother Cæsar were so widely famed. They were marvellous things, those Borgia decoctions--marvellous and abominable." "Horrible!" agreed Narkom, a curious shadow of unrest coming over him at this subject rising at this particular time. "Modern chemistry has, I believe, been quite unable to duplicate them. There is, for instance, that appalling thing the aqua tofana, the very fumes of which caused instant death." "Aqua tofana was not a Bornean poison, my friend," said Cleek, with a smile. "It was discovered more than two hundred years after _their_ time--in 1668, to be exact--by one Jean Baptiste de Gaudin, Signeur de St. Croix, the paramour and accomplice of that unnatural French fiend, Marie Marquise de Brinvilliers. Its discoverer himself died through dropping the glass mask from his face and inhaling the fumes while he was preparing the hellish mixture. The secret of its manufacture did not, however, die with him. Many chemists can, to-day, reproduce it. Indeed, I, myself, could give you the formula were it required." "_You?_ Gad, man! what don't you know? In heaven's name, Cleek, what caused you to dip into all these unholy things?" "The same impulse which causes a drowning man to grip at a straw, Mr. Narkom--the desire for self-preservation. Remember what I was in those other days, and with whom I associated. Believe me, the statement that there is honour among thieves is a pleasant fiction and nothing more; for once a man sets out to be a professional thief, he and honour are no longer on speaking terms. I never could be wholly sure, with that lot; and my biggest _coups_ were always a source of danger to me after they had been successfully completed. It became necessary for me to study _all_ poisons, all secret arts of destruction, that I might guard against them and might know the proper antidote. As for the rest--Sh! Mumm's a fine wine. Here comes the landlady with the tea. We'll drop the 'case' until afterward."