The Medical Block--later called simply the 1914 Building--was the first real home of the Mayo Clinic. Until its construction, the Mayo practice had operated out of rented offices in the Ramsey Block and the Masonic Temple. The 1914 building consolidated the Mayo group operation and gave them the freedom to begin to implement some of the groundbreaking practices which would cement the already-famous doctors' reputations as among the best in the world.
I love the random cars that have been pasted in. Notice that a large addition to the Zumbro hotel has replaced the old West Hotel that sat between Mayo and the Zumbro in the earlier photos.