Opiz that he had finished the twelfth volume of his Memoirs, with his age at forty-seven years [1772]. "Our late friend, the worthy Count Max Josef Lamberg," he added, "could not bear the idea of my burning my Memoirs, and expecting to survive me, had persuaded me to send him the first four volumes. But now there is no longer any questions that his good soul has left his organs. Three weeks ago I wept for his death, all the more so as he would still be living if he had listened to me. I am, perhaps, the only one who knows the truth. He who slew him was the surgeon Feuchter at Cremsir, who applied thirty- six mercurial plasters on a gland in his left groin which was swollen but not by the pox, as I am sure by the description he gave me of the cause of the swelling. The mercury mounted to his esophagus and, being able to swallow neither solids nor fluids, he died the 23rd June of positive famine . . . . The interest of the bungling surgeon is to say that he died of the pox. This is not true, I beg, you to give the lie to anyone you hear saying it. I have before my eyes four hundred and sixty of his letters over which I weep and which I will burn. I have asked Count Leopold to burn mine, which he had saved, and I hope that he will please me by doing it. I have survived all my true friends. 'Tempus abire mihi est' Horace says to me.
"Returning to my Memoirs . . . I am a detestable man; but I do not care about having it known, and I do not aspire to the honor of the detestation of posterity. My work is full of excellent moral instructions. But to what good, if the charming descriptions of my offences excite the readers more to action than to repentance? Furthermore, knowing readers would divine the names of all the women and of the men which I have masked, whose transgressions are unknown to the world, my indiscretion would injure them, they would cry out against my perfidy, even though every word of my history were true . . . . Tell me yourself whether or not I should burn my work? I am curious to have your advice."
On the 6th May 1793, Casanova wrote Opiz: "The letter of recommendation you ask of me to the professor my brother for your younger son, honors me; and there is no doubt that, having for you all the estimation your qualities merit, I should send it to you immediately. But this cannot be. And here is the reason. My brother is my enemy; he has given me sure indications of it and it appears that his hate will not cease until I no longer exist. I hope that he may long survive me and be happy. This desire is my only apology."
"The epigraph of the little work which I would give to the public," Casanova wrote the 23rd August 1793, "is 'In pondere et mensura'. It is concerned with gravity and measure. I would demonstrate not only that the course of the stars is irregular but also that it is susceptible only to approximate measures and that consequently we must join physical and moral calculations in establishing celestial movements. For I prove that all fixed axes must have a necessarily irregular movement of oscillation, from which comes a variation in all the necessary curves of the planets which compose their eccentricities and their orbits. I demonstrate that light has neither body nor spirit; I demonstrate that it comes in an instant from its respective star; I demonstrate the impossibility of many parallaxes and the uselessness of many others. I criticize not only Tiko-Brahi, but also Kepler and Newton . . . .
"I wish to send you my manuscript and give you the trouble of publishing it with my name at Prague or elsewhere . . . . I will sell it to the printer or to yourself for fifty florins and twenty-five copies on fine paper when it is printed."
But Opiz replied:
"As the father of a family, I do not feel myself authorized to dispose of my revenues on the impulse of my fancy or as my heart suggests.... and no offer of yours could make me a book-seller."
This shows plainly enough that Opiz, for all his interest in Casanova, had not the qualities of true friendship.