Edward Douglass White, Henderson Bridge Company v. Commonwealth of Kentucky…
“ It being beyond dispute, therefore, that the sum of taxation in this case was fixed almost exclusively by the gross earnings from interstate commerce, who, may I ask, can point out the distinction between taxing the gross earnings derived from interstate commerce and taxing a valuation based on such earnings? The elementary principle so often applied by the court, that a tax which may not be imposed directly cannot be levied indirectly, is decisive. ”
