Mahlon Pitney, United States Glue Company v. Town of Oak Creek…
“ Conceivably it may be sufficient to make the difference between profit and loss, or to so diminish the profit as to impede or discourage the conduct of the commerce. A tax upon the net profits has not the same deterrent effect, since it does not arise at all unless a gain is shown over and above expenses and losses, and the tax cannot be heavy unless the profits are large. Such a tax, when imposed upon net incomes from whatever source arising, is but a method of distributing the cost of government, like a tax upon property, or upon franchises treated as property ”
