Lin asked about her ancestor Baer Cohn. I've been looking into the
question of Jewish names before Napoleonic name-adoption, and it seems
that COHN is not a patronymic but a regular surname which can be passed
on >from father to child. My 5x great-grandfather was Benjamn COHEN and
his daughter, my 4x great-grandmother was Elke COHEN, and he sisters
also used that surname. It must have been the choice in the case of
Baer COHN's descendants, not to use that surname as they were entitled
to, but HERZ instead.
As for the father's name: the thing about death certificates is that
they were often issued by non-Jewish officials who didn't understand
Jewish naming practices, so the name quoted in this case must be
viewed with suspicion. It may just have been the popular name he went
by in his old age - the old COHEN who is related to Baer, now the
head of the household, rather than the first name given to the old man
at his Brith.
Eva Lawrence, St Albans, UK. firstname.lastname@example.org