[...] I am sending you to-day a pianoforte arrangement from Tristan, in which I have marked the alterations necessary for Ander. As Esser, and I presume also Ander, are not at present in Vienna, I believe the best thing I can do is to leave the affair in your hands. [...] In the meantime, however, perhaps it would be as well to see to the copying at once, as there are, as you will see, a few passages to be altered, notably in the orchestral part. I would like to ask you to undertake the transposition towards the end of Act II. yourself, as I am afraid that a copyist would not do it properly. [...] Herr and Frau Dustmann are still in Vienna, I suppose? [...] If Isolde be studying her part already, she is not on any account to be despondent; I have boundless confidence in her! [...] I had not much opportunity to enjoy the society of Liszt, as he was the property of an exceedingly wide circle. He left here last Saturday with Tausig. I saw more of Tausig, but on the whole things were not very happy, chiefly on account of my uncertain situation and—of Paris. Tausig is gadding about Leipzig and Weimar now. The good-hearted little fellow is trying to be of use to me. [...]
I am conscientiously bearing your opera subject in mind, but I utterly lack the right mood for putting down properly on paper my scheme of alteration for you. Be sure, though, that I shall do it, and soon. I know myself! But one cannot do anything without the right mood!
The pleasant frame of mind induced by Vienna is unfortunately quite blighted. When I look forward now to my difficult projects there, I feel more fear than joy, and at the same time the thought of being able at last to hear this music is the one thing that fills me with the wish to live!
Give my kindest regards to my new friends in Vienna, particularly Herr Dr. Standhartner, to whom I took a great liking. [...]
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 492