Dear Franz,
Believe me, by all that is sacred to you and me, that I am ill, and require the most perfect rest and care today, in order, let us hope, to enjoy you again tomorrow. A very considerable, though welcome and wholesome, catarrh weighs down my limbs like lead. It developed during last night, together with an inflamed throat and other addenda. The slightest excitement would impede my recovery.
Au revoir in a rational manner tomorrow.
Source: Project Gutenberg eBook #4234, Correspondence of Wagner and Liszt — Volume 2, No. 225