[...] I am now in an indescribable passion of work. These last days I have been mad to finish my big Nibelung drama, and yesterday I did finish it completely. But you ought to know what I mean by "working" nowadays. My nerves are so upset that if I work two hours before midday, I have to spend all the rest of the day and night carefully recovering from these two tempestuous hours in order to fit myself for another two hours' work on the next day. I have to fear, and avoid, the least effort or excitement; I dare not read nor do anything else to excite my brain. Often when I have had to answer a business letter shortly I have paid for the overstrain to the utmost.—Under such circumstances I have barely nibbled at your Songs, but even this nibbling has filled me with such hope of refreshing delights that I have promised myself with full solemnity to begin my new career as a musician (now imminent,—for I have only the music of my Nibelung dramas to make now) by bathing in your copious brooks of song, whereby I may become again a musician indeed.
To-day I am going for a few days to a family of friends in the country for a change. After that I still have to write troublesome, and to me tormenting, introductions to the performance of The Flying Dutchman and Lohengrin (which is also to be given now), but when this is done I hope to be free and you shall baptise me a musician once more. Then shall I be able to thank you properly! [...]
Source: Letters of Richard Wagner, Vol. 1, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 232