The recipient may be George Frederick Watts.
The letter reads, in full: "I do not remember the article to which Mr McColl, with so much tact, drew your attentions. However I don't fancy I meant any malice, and I don't believe, as a rule, that anybody does. Give me a list of enemies, and let me ask you all to dinner; these things are merely the grown up form of snow ball fights, a delicious sport in which we can no longer take a hand. I really am unaware, for one, of having any literary foes, though I daresay the playful skit is occasionally hurled at me. We all have our share of that, but I never see why anybody should mind it: as long as one is not accused of crimes. Yours very sincerely, A Lang / But, to be serious, I do not believe that Mr. Saintsbury has any enmity to you. I never heard him, nor, to the best of my memory, any man, speak a word against you, and it really makes me unhappy to see what comes of unsigned articles, in a world (of letters) taken too seriously."