“ For the calendar year 1924 and the calendar year 1925, a tax equal to the sum of the following is hereby imposed upon the transfer by a resident by gift during such calendar year of any property wherever situated, whether made directly or indirectly, and upon the transfer by a nonresident by gift during such calendar year of any property situated within the United States, whether made directly or indirectly: 1 per centum of the amount of the taxable gifts not in excess of $50,000 ”

“ Upon this among other considerations the rule is settled that as between two possible interpretations of a statute, by one of which it would be unconstitutional and by the other valid, our plain duty is to adopt that which will save the Act. Even to avoid a serious doubt the rule is the same. ”

“ It seems wholly unreasonable that one who, in entire good faith and without the slightest premonition of such consequence, made absolute disposition of his property by gifts should thereafter be required to pay a charge for so doing. ”