More amusing than Hegel's commentary is that of Mr. Jules Janin,  from which you will find extracts in the appendix to the little volume. This cardinal de la mer [sea-cardinal] feels the lack of a moral in Diderot's Rameau and has therefore set the thing right by the discovery that all Rameau's contrariness arises from his vexation at not being a " born gentleman." The Kotzebue-ish rubbish which he has piled up on this cornerstone is being performed as a melodrama in London. From Diderot to Jules Janin is no doubt what the physiologists call regressive metamorphosis. The French intellect as it was before the revolution and under Louis Philippe!...  Le Neveu de Rameau [Rameau's Nephew], a satirical dialogue by Diderot (1713-1784), one of the leading French materialist philosophers of the 18th century, editor of the Encyclop die and a brilliant man of letters. The passage from Hegel quoted here by Marx is from the Ph nomonolgie des Geistes (Phenomenology of Mind), [Ed. Eng. ed.]  Janin, Jules (1804-74) French bourgeois author and literary critic with a popular reputation in bourgeois circles.
Letters: Marx-Engels Correspondence 1869