Riot Diet

* Detroit -- Violence was subsiding yesterday, and there was talk of withdrawing Federal troops. The death toll stood at 38 in the nation's costliest riot.

* Albany -- Gangs of young Negroes attacked shops in the main business district.

* Mt. Vernon, N.Y. -- A ban on liquor and a curfew were imposed after two nights of mob disorder.

* Scattered outbreaks were also reported in San Francisco; Sacramento; Cal.; Waterbury, Conn; Phoenix, Ariz; Roanoke, Va.; Kalamazoo, Mich.; and Watts.