2. Van Gogh may be alluding here to the dragging on of the relationship between the husband and wife in
Thérèse Raquin, who want to leave each other but nevertheless do not do it: ‘And they stayed out of cowardice and dragged wretchedly on in the horror of their existence.’ (Et ils restaient par lâcheté, ils restaient et se traînaient misérablement dans l’horreur de leur existence.) See Zola 1966-1970, vol. 1, p. 653 (chapter 30).