From Wikipedia: http://en.wikipedia.org/wiki/Old_Dispensary

The Old Dispensary, also known as Ithnashiri Dispensary, is a historical building in Stone Town, Zanzibar. It is located on the seafront, in Mizingani Road, halfway between the Palace Museum and the harbour. It owes its name to the fact that it served as a dispensary in the first half of the 20th century.