Sorry to be so long in replying to Mary's query.

     I have seen a couple of c. 1930s apartment houses here in DC that have
     louvered doors on the corridor side and solid doors on the inside.  I
     always assumed they were for summer ventilation, so people could keep their
     doors open on hot nights (which Washington has more than its share of,
     particularly this year), get some cross ventilation, and still have
     reasonable privacy and security.  Standards for both of these commodities
     appear to have been lower in the 1930s than they are now.  Same principle
     as transoms.  Some of these buildings may have been built under government
     housing programs--that might be an avenue to check.

     I think I have also seen early 19th century louvered doors on offices in
     Robert Mills/T. U. Walter's old General Post Office here in town (usually
     called the Tariff Commission building, across from the Patent Office), but
     as I remember these were partial swinging doors, sort of like the saloon
     doors that you used to see in old Western movies, but with louvers.

     Marilyn Harper