I have a correction and two additions to Malka's translation of Nathan's epitaph.
From the picture the death date seems to be 24 of Av 5650. There are additional details. It says that he passed away on a Monday and was buried on Tuesday 26 of Av.
The English date at the bottom says August 11th 1890.
This corresponds to 25 of Av, which actually was a Monday. Since the picture is pretty clear, 24 is not a misreading but an error of the stone graver between the letter dalet (ד) and he (ה) .
Additionally the name of the deceased is preceded by the title of Doctor, not necessary indicating an M. D.