This tidbit from the chapter on Seventh Street in my newly-arrived 1937 WPA guide on Washington:

Seventh Street in this region, and immediately east and west of the street itself, becomes invaded with dilapidated houses, small shops, pawnbrokers’ officers, and teeming restaurants. The Old Indian Herb Store, at No. 1726, sells every kind of remedy – from cures for tuberculosis to love philtres guaranteed to conquer the most reluctant. Small clothing stores hang half their merchandise outside, and the passer-by who tarries is likely to be pulled in by clerks.

Unfortunately it looks like No. 1726 is long gone, replaced with an uninspired office building.