"before the 1921 Act this Court had indicated (see Eisner v. Macomber, 252 U.S. 189, 207, 64L.ed 521, 9 A.L.R. 1570, 40 S. Ct. 189), what it later held, that 'income,' as used in the revenue acts taxing income, adopted since the 16th Amendment, has the same meaning that it had in the Act of 1909. Merchants; Loan & T. Co. v. Smietanka, 255 U.S. 509, 519, 65 L.ed. 751, 755, 15 A.L.R. 1305, 41 S. Ct. 386; see Southern Pacific Co. v. Lowe. 247 U.S. 330, 335, 62 L.ed. 114, 1147, 38 S. Ct. 540. " The 16th amendment did not extend the taxing power.