Hennepin County Medical Center, Minnesota's biggest public hospital, opened its first retail clinic in February, at a Wal-Mart in Bloomington, almost 10 miles away from its main campus. Its debut comes at a strange time in the retail clinic business: There are now about 1,200 outlets around the country, according to the Convenient Care Association, a trade group. Yet while many consumers like the retail clinics, operators have found it hard to make money, mainly because the business is highly seasonal, the Minneapolis Star Tribune reports.