398 HARVARD LAW REVIEW and that under other circumstances and by other methods it may not. Such a declaration would have turned attention more directly to the circumstances and to the methods. The rules of law might then have been worked out on matter-of-fact lines which avoided logical inconsistency by avoiding fictions and the semblance of generality when the generaUty was shadow and not substance. We have already considered the reasons why it is as wise and necessary to allow the states to tax interstate commerce as to allow them to tax property employed in interstate commerce.^^ Exemp- tion of such commerce from burdens which local commerce must bear would be equivalent to a bounty on interstate commerce. The withholding of such a bounty from interstate commerce ought not in wisdom to be regarded as "a regulation of it in a constitu- tional sense." But the court must be zealous to restrain the states from obtaining revenue from extraterritorial sources or from im- posing cumulative exactions on interstate business without simi- larly burdening all local business. Owing to the ubiquity of property taxation and to the fact that the value of real estate and of stocks and bonds and similar obligations bears a close relation to the income from such property, a state "is less likely to attempt to or effect injurious regulation," when it "is trying simply to value property" than "when it is aiming directly at the receipts from interstate commerce." ^® On the other hand, the states have been more sporadic and selective in their impositions on occupations and on income. They must therefore be held to strict account when they tax income from interstate commerce. They must estabHsh that the burden is a general and not a discriminatory one. The court is satisfied when the state shows that the income is taken as a fair measure of the value of property assessed for taxa- tion, or when a tax on income is in substitution for a tax on property. It was satisfied in the Ficklea case when gross receipts were taxed in the absence of taxation on property because there was no property to tax. It has been satisfied more recently with a state-wide income tax measured by net rather than gross receipts. ^^ In the presence of " 32 Harv. L. Rev. 260-62.
- From Mr. Justice Holmes' opinion in the Galveston case, quoted on page 394,
supra. '^ United States Glue Co. v. Oak Creek, 247 U. S. 321, 38 Sup. Ct. Rep. 499 (1918). See pages 415-16, infra.
