Though it probably went mostly unnoticed in the cacophony of health care stories, last week's news that Walgreen's had bought the two largest and most well-established worksite clinic firms, iTrax and Whole Health Management, was a harbinger of very big changes in health care. Walgreens, the ubiquitous drugstore company that, with Wal-Mart and CVS, has already leveraged its pharmacy platform to establish a strong footprint in retail clinics, undoubtedly startled many health care observers with its announcement. After all, isn't the company doctor a relic?