Hospital hydrotherapy. Physiotherapy nurse (centre) supervising patients using water baths during a session of hydrotherapy, a form of physiotherapy (physical therapy). Modern physiotherapy was established in the late 19th century, using massage, manual therapy and hydrotherapy (as here) to increase joint mobility in cases of injury or orthopaedic conditions. This session is taking place at the Walter Reed General Hospital (later the Walter Reed Army Medical Center), established in Washington DC, USA, in 1909. Photographed between 1920 and 1921.