Storefront or retail clinics seemed to be in boundless expansion a year ago, but now may be shrinking along with everything else in the economy.  Wal-Mart is closing 44 of its clinics and, apparently, holding off opening others.  Walgreens, however, expects to add 100 retails clinics to its pharmacies by the middle of next year.  Typically, one of these clinics cost about three quarters of a million dollars to install.  The question remains whether or not American consumers will switch from primary care to retail clinics for small emergencies.          MORE