Pittsburgh, Pennsylvania: [ University of Pittsburgh ] 1955. First Edition. Single 8 1/2 x 11 inch sheet. A TLS (typed letter signed) from Jonas Salk dated August 25, 1955 on University of Pittsburgh School of Medicine letterhead thanking a Mr. Arthur Wilson for his good wishes. 'It was very kind of you to express your good wishes; we appreciate having them.' SIGNED boldly in ink 'Jonas E. Salk'. Creasing as expected for a mailed letter. Includes the matching mailing envelope with Virus Research Laboratory return address. Near Fine. 
Dr. Jonas E. Salk is best known for his discovery of a safe and effective polio vaccine. His development of the vaccine was completed during a very intense period of several years (even though other scientists had been pursuing different research paths since the late 1930s). The new vaccine was officially announced on April 12, 1955. A competing 'live-virus' vaccine by Dr. Sabin was eventually discontinued in favor of Salks 'dead-virus' vaccine because of the greater efficacy of Salk's vaccine.