title: The specificity and stability of old tuberculin and tuberculin PPD.
mesh_terms: D000818:Animals; D001681:Biological Assay; D002417:Cattle; D003470:Culture Media; D006168:Guinea Pigs; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D011309:Preservation, Biological; D014373:Tuberculin / Q000592:standards*; D014374:Tuberculin Test
chemical_list: D003470:Culture Media; D014373:Tuberculin