The history of taxation shows that taxes which are inherently excessive are not paid. The high rates inevitably put pressure upon the taxpayer to withdraw his capital from productive business and invest it in tax-exempt securities or to find other lawful methods of avoiding the realization of taxable income. The result is that the sources of taxation are drying up; wealth is failing to carry its share of the tax burden; and capital is being diverted into channels which yield neither revenue to the Government nor profit to the people.