Once we had reached the Archives, we searched in vain for some trace of Ugonio and Ciacconio. The two must be waiting there already, well hidden in some corner.
'It is we! Is all well?' asked Atto in a loud voice.
From behind some archway enveloped in darkness, Ciacconio's unmistakeable grunt replied in the affirmative.
We therefore resumed our exploration and, as we walked, again began to converse.
It had, we both agreed, been inexcusably short-sighted on our part not to have collated the very clear clues which had come to our attention during the previous few days. Fortunately, it was still possible to catch the mad horse of truth by the mane. Atto tried once more to sum up the elements of which we were aware: 'Dulcibeni worked for the Odescalchi, as an accountant or something of the kind. He had a daughter called Maria, by a Turkish slave. The maiden was abducted by the former slave-trader Feroni and by his right-hand man Huygens, surely in order to satisfy one of the latter's caprices. Maria was probably taken very far away, to somewhere in the north. In order to trace her, Dulcibeni then turned to the Odescalchi, but they did not help him. This is why Dulcibeni detests them, and will naturally feel special hatred for the powerful Cardinal Benedetto Odescalchi, who has in the meantime become Pope. Moreover, after the abduction, something strange happens. Dulcibeni is assaulted and thrown from a window, probably with the intention of killing him. Are we agreed?'
'Agreed.'
'And here the first obscure point arises: why would someone, acting perhaps on the orders of Feroni or the Odescalchi, have wished to be rid of him?'
'Perhaps to prevent him from recovering his daughter.'
'Perhaps,' said Atto with scant conviction. 'But you have heard that all his searches were in vain. I am more inclined to believe that Dulcibeni had become a danger for someone.'
'But Signor Atto, why was Dulcibeni's daughter a slave?'
'Did you not hear Tiracorda? Because her mother was a Turkish slave whom Dulcibeni was unwilling to marry. I am not well informed on the trade in negroes and Infidels, but-according to Dulcibeni- the bastard child was also considered to be a slave of the Odescalchi. I only wonder: why did Huygens and Feroni not simply buy her?'
'Perhaps the Odescalchi did not wish to sell her.'
'Yet they did sell her mother. No, I think it was rather Dulcibeni who opposed his daughter's being ceded; that would explain why she was abducted, perhaps with the support of the Odescalchi themselves.'
'Do you mean to say that such an abominable action might have had the backing of the family?' I asked, horrified.
'Surely. And perhaps that of Cardinal Benedetto Odescalchi himself, who has since become Pope. Do not forget that Feroni was exceedingly wealthy and quite powerful. That would suffice to explain why the Odescalchi should not have wished to help Dulcibeni to find his daughter.'
'But what means had Dulcibeni to oppose the sale, if the girl was the property of the Odescalchi?'
'You rightly ask: what means had he? That, I think, is the point. Dulcibeni must have unsheathed an arm that posed a real threat to the Odescalchi and left them no choice but to arrange the abduction with Feroni and to try to have Dulcibeni silenced forever.'
Feroni: I was about to tell the abbot that the name did not sound new to me. However, being unable to recall where I had heard it, I held my peace.
'An arm against the Odescalchi. A secret perhaps… who knows,' murmured the abbot, with a Iubricious gleam in his eyes.
An inadmissible secret in the past of the Pope: I understood that Atto Melani, secret agent of His Most Christian Majesty, would have given his life to know what that might have been.
'We must come to a conclusion, damn it!' he exclaimed at the end of his cogitations. 'But first, let us recapitulate: Dulcibeni hatches the idea of assassinating no less a personage than the Pope. He can surely not hope to obtain an audience with the Pontiff and to stab him with a knife. How can one kill a man from a distance? One may attempt to poison him; but it is exceedingly difficult to introduce poison into the Pope's kitchens. Dulcibeni, however, works out a more refined solution. He remembers that he has an old friend who will serve his purpose: Giovanni Tiracorda, Physician in Chief to the Pope. Pope Odescalchi-and this Dulcibeni knows-has always suffered from delicate health. He is Tiracorda's patient, and Dulcibeni can take advantage of the situation. Just at this moment, moreover, tormented by the fear that the Christian armies might be defeated in Vienna, the condition of Pope Innocent XI has worsened. The Pope is treated by blood-letting, and this is effected by means of leeches which, of course, feed on blood. So, what does Dulcibeni do? Between one riddle and another, he gets Tiracorda drunk. This is not too difficult a task, because the physician's wife, Paradisa, is a bigot and half-crazed: she believes that alcohol leads to the damnation of the soul. So Tiracorda is compelled to drink in secret, and thus almost always to gulp down large quantities at speed. As soon as he is inebriated, his friend Dulcibeni infects the leeches intended for treating the Pope with the pestiferous humour which he has produced on his islet. The little creatures will sink their teeth into the Pontiff's holy flesh and he will be attacked by the infection.'
'How horrible!'
'I would not say that. This is simply what a man thirsting for vengeance is capable of. Do you recall our first incursion into Tiracorda's house? Dulcibeni asked him: 'How are they?'', referring, as we now know, to the leeches which he planned to infect. Then, however, Tiracorda accidentally broke the bottle of liquor and Dulcibeni was compelled to postpone his operation. Last night, however, his plans progressed smoothly. While he was infecting the leeches, he pronounced the words, 'For her'': he was fulfilling his vendetta against the Odescalchi for the abduction of his daughter.'
'But,' I observed, 'he needed a quiet place in which to prepare his plan and to carry out his operations.'
'Bravo. And above all to cultivate the pestiferous humour, using arts unknown to us. After capturing rats, he caged them on his island and inoculated them with the infection. Then he extracted their blood and so treated it as to produce the infected humour. It was surely he who lost the leaf from the Bible in the galleries.'
'So could he also have stolen my little pearls?'
'Who else? But, do not interrupt me,' said Atto, cutting me short, and adding: 'After the beginning of the quarantine and your master's being taken ill, Dulcibeni, in order to continue to have access to the underground galleries and, thus, to the isle of the Mithraeum, had to filch a key from Pellegrino's ring and to have a copy made by a locksmith. He wrapped a copy of the key in Komarek's page from the Bible; but, what with all that trafficking with rats, leeches and alembics, it was inevitable that he should have accidentally stained it with blood.'
'On the island, we also found a vase for leeches almost identical to Tiracorda's,' I observed, 'and then, there were all those instruments…'
'He used the vase, I imagine, to keep a few leeches in and perhaps to make certain that they could feed on infected blood without themselves being killed by it. When, however, he understood that he was not the only one to take walks in the underground galleries, and that someone might be on his trail, he got rid of the little creatures which might have provided evidence of his criminal designs. The apparatus and instruments on the islet, however, were used not only for his experiments on rats, but also for preparing the pestiferous humour. That is why everything called to mind the cabinet of an alchemist: alembics, unguents, crucibles…'
'And that sort of gallows?'
'Who knows? Perhaps to keep the rats still while he bled them, or to cut them up and collect their blood.'
And that was why, we repeated once more, we had found dying rats in the galleries: they had either escaped from or survived Dulcibeni's experiments, and we had encountered them before they died. Finally, the glass phial full of blood which we had found in gallery D had certainly been lost by Dulcibeni, who had perhaps attempted unsuccessfully to infect his friend Tiracorda's leeches directly with the rats' blood.
'But in the underground galleries, we also found leaves of mamacoca,' I observed.
'That, I am unable to explain,' admitted Abbot Melani. 'Those had nothing to do with the pestilence or with Dulcibeni's plot. Another point: I cannot conceive how it was possible for Dulcibeni, day after day, and even at night, to run, to row, to climb and to escape our attempts to stalk him with the energy of a young boy. It seems almost as though someone must have helped him.'
While we were engaged in such discussions, we came to the trapdoor at the intersection between conduits A and B. The left-hand branch of B was the last of the three passages which we had undertaken to explore a few days
