The examination or testing of food, fluids, or other articles made subject by law to such examination, to ascertain their fitness for use or commerce. People v. Compagnie Generale Transatlan- tique (C. C.) 10 Fed. 361; Id., 107 U. S. 59, 2 Sup. Ct. 87, 27 L. Ed. 383; Turner v. Maryland, 107 U. S. 38, 2 Sup. Ct. 44, 27 L. Ed. 370. Also the examination by a private person of public records and documents; or of the books and papers of his opponent in an ac- tion, for the purpose of better preparing his own case for trial.