https://marxists.architexturez.net/archive/marx/works/1862/letters/62_07_30a.htm

The Jewish nigger Lassalle who, I’m glad to say, is leaving at the end of this week, has happily lost another 5,000 talers in an ill-judged speculation. The chap would sooner throw money down the drain than lend it to a ‘friend’, even though his interest and capital were guaranteed. In this he bases himself on the view that he ought to live the life of a Jewish baron, or Jew created a baron (no doubt by the countess). Just imagine! This fellow, knowing about the American affair, etc., and hence about the state of crisis I’m in, had the insolence to ask me whether I would be willing to hand over one of my daughters to la Hatzfeldt as a ‘companion’, and whether he himself should secure Gerstenberg’s (!) patronage for me! The fellow has wasted my time and, what is more, the dolt opined that, since I was not engaged upon any ‘business’ just now, but merely upon a ‘theoretical work’, I might just as well kill time with him! In order to keep up certain dehors vis-à-vis the fellow, my wife had to put in pawn everything that wasn’t actually nailed or bolted down!

It is now quite plain to me — as the shape of his head and the way his hair grows also testify — that he is descended from the negroes who accompanied Moses’ flight from Egypt (unless his mother or paternal grandmother interbred with a nigger). Now, this blend of Jewishness and Germanness, on the one hand, and basic negroid stock, on the other, must inevitably give rise to a peculiar product. The fellow’s importunity is also nigger-like.

(http://www.autoadmit.com/thread.php?thread_id=5554341&forum_id=2#47835545)