[...] I should have been very glad to hear from you and Cosima. I much enjoyed seeing her at Reichenhall. If only the naughty child would look after herself properly! I hear that she is visiting her father again—if only she doesn't let herself be persuaded there into small but, to her, very harmful excesses! She's a wild child; that I say and that I stand by! But she has nobility. You must make use of that to persuade her to give up even little injurious habits. Pride must make her grow even-tempered and calm. I was very much reassured by her appearance. No doubt all will be well with her! [...]
I often see Tausig and Cornelius. Mme. Dustmann is equal to Isolde already and sings the part ravishingly. But Ander is nowhere near the Tristan as yet.—
Source: Letters of Richard Wagner, Vol. 2, selected and ed. Wilhelm Altmann, trans. M. M. Bozman (J. M. Dent & Sons, 1927), No. 499