And when I sit down to write I am so abstracted by recollections of what I have seen that I leave the letter. For instance at the present occasion I was writing to you and going to say something about Arles as it is–and as it was in the old days of Boccaccio. Well, instead of continuing the letter I began to draw on the very paper the head of a dirty little girl I saw this afternoon whilst I was painting a view of the river with a greenish yellow sky.