Spain cover 1952 Spanish Philippino Postal Convention sent Valencia to USA

Cover with cachet of a Hispano-Philippino postal covention held in Madrid in 1952.  Franked with a 50c Franco and 10c Anti-Tuberculosis Fund postmarked Valencia Dec. 13, 1952.  

Cover addressed to Seattle, WA USA.  Cut open on left side.  Some toning spots front and back.