“ At most, exportation is affected only indirectly and remotely. The tax is levied after exportation is completed, after all expenses are paid and losses adjusted, and after the recipient of the income is free to use it as he chooses. Thus what is taxed-the net income-is as far removed from exportation as are articles intended for export before the exportation begins. ”

“ The Constitution broadly empowers Congress not only 'to lay and collect taxes, duties, imposts, and excises,' but also 'to regulate commerce with foreign nations.' So, if the prohibitory clause invoked by the plaintiff be not in the way, Congress undoubtedly has power to lay and collect such a tax as is here in question. ”

“ As pointed out in recent decisions, it does not extend the taxing power to new or excepted subjects, but merely removes all occasion, which otherwise might exist, for an apportionment among the states of taxes laid on income, whether it be derived from one source or another. ”