(dissenting). The provision interpreted in the majority opinion was intended to avoid double taxation by Wisconsin of corporate profits. In the original Income Tax Law and until 1927 this provision was worded so as to accomplish its object with exact nicety. Where only a *240percentage of a corporation’s net income was taxed in Wisconsin only that same percentage of its dividends could be deducted by a Wisconsin taxpayer who received them. See Van Dyke v. Milwaukee (1915), 159 Wis. 460, 466, 146 N. W. 812.
In 1927 the law was changed into substantially the form controlling this case. Ch. 539, Laws of 1927. It permitted complete deduction of dividends from some corporations and completely denied deduction of dividends from others. The purpose of the change can only have been administrative convenience. Instead of applying the exact percentage of a corporation’s net corporate income taxed in Wisconsin to its dividends in order to determine the amount a taxpayer could deduct, an arbitrary line was drawn and the dividends of corporations falling on one side of the line could be deducted in toto, those of others not at all.
I conclude that the legislature, which was relieving the commission from a burden of arithmetical computation, did not intend to saddle it with the burden of determining the frequently complex question of fact whether a corporation’s principal business was attributable to Wisconsin. Moreover, this happens to be an instance where an arbitrary percentage test is far more relevant to the purpose of the statute than is some other concept of principal business. Finally, for twenty-four years every Wisconsin taxpayer was informed by official instructions, as well as by the terms printed on his return, that the 50 per cent test was THE test of deductibility of dividends. Thousands of taxpayers throughout that period presumably figured their deductions and paid their taxes in reliance upon the position of the commission and the department that the 50 per cent test controlled.
The rule in favor of giving effect to all the words used in the law should not be followed so far as to obstruct the general purpose of the law and at most should raise an *241ambiguity which can be resolved by long-continued administrative construction. The judgment of the circuit court ought to be affirmed.
I am authorized to state that Mr. Justice Broadfoot joins in this dissent.