Sometime after this and following his quarrel with M. Opiz, Casanova evidently passed through a period of depression, as indicated by a manuscript at Dux, headed “Short reflection of a philosopher who finds himself thinking of procuring his own death,” and dated “the 13th December 1793, the day dedicated to S. Lucie, remarkable in my too long life.”

“Life is a burden to me.  What is the metaphysical being who prevents me from slaying myself?  It is Nature.  What is the other being who enjoins me to lighten the burdens of that life which brings me only feeble pleasures and heavy pains?  It is Reason.  Nature is a coward which, demanding only conservation, orders me to sacrifice all to its existence.  Reason is a being which gives me resemblance to God, which treads instinct under foot and which teaches me to choose the best way after having well considered the reasons.  It demonstrates to me that I am a man in imposing silence on the Nature which opposes that action which alone could remedy all my ills.

“Reason convinces me that the power I have of slaying myself is a privilege given me by God, by which I perceive that I am superior to all animals created in the world; for there is no animal who can slay itself nor think of slaying itself, except the scorpion, which poisons itself, but only when the fire which surrounds it convinces it that it cannot save itself from being burned.  This animal slays itself because it fears fire more than death.  Reason tells me imperiously that I have the right to slay myself, with the divine oracle of Cen:  ’Qui non potest vivere bene non vivat male.’  These eight words have such power that it is impossible that a man to whom life is a burden could do other than slay himself on first hearing them.”

Certainly, however, Casanova did not deceive himself with these sophisms, and Nature, who for many years had unquestionably lavished her gifts on him, had her way.

Over the end of the year, the two mathematicians, Casanova and Opiz, at the request of Count Waldstein, made a scientific examination of the reform of the calendar as decreed the 5th October 1793 by the National Convention.

In January 1795, Casanova wrote to the Princess Lobkowitz to thank her for her gift of a little dog.  On the 16th the Princess wrote from Vienna: 

“Monsieur,

“I am enchanted at the charming reception you accorded the dog which I sent you when I learned of the death of your well-loved greyhound, knowing that she would nowhere be better cared for than with you, Monsieur.  I hope with all my heart that she has all the qualities which may, in some fashion, help you to forget the deceased . . . .”