Adolf Gross tells me that you would like to have a photograph of my husband, and that a signed one. Here it follows with a smile from my husband, as he knows how many of his letters you possess, and evidences of his friendliest esteem. What a friend you have proved yourself again! And how our "system" has been justified of its result! Accept our thanks and greetings, in most cordial and unalterable friendship to you and your dear ones, from all at Wahnfried.
Source: Letters of Richard Wagner to Emil Heckel, with a Brief History of the Bayreuth Festivals, trans. William Ashton Ellis (Grant Richards, 1899), No. 95