[T]he command of the amendment that all income taxes shall not be subject to the rule of apportionment by a consideration of the source from which the taxed income may be derived forbids the application to such taxes of the rule applied in the Pollock case by which alone such taxes were removed from the great class of excises, duties, and imposts subject to the rule of uniformity and were placed under the other or direct class.240 U.S. 1 18–19 (1916).
[t]he command of the amendment that all income taxes shall not be subject to the rule of apportionment by a consideration of the source from which the taxed income may be derived forbids the application to such taxes of the rule applied in the pollock case by which alone such taxes were removed from the great class of excises duties and imposts subject to the rule of uniformity and were placed under the other or direct class240 us 1 18–19 (1916)