premise: One is entitled to speculate on what outrageous proposal the narrator had made in Proust's Remembrance of Things Past, Vol. 2'Cities of the Plain (translated by C. K. Scott Moncrieff'Modern Library, N.Y., 1934, Page 90) to cause the Duchess to say,  Apart from your balls, can't I be of any use to you? 
hypothesis: The duchess asked if she could help him.