This chapter shall not prevent aliens from acquiring lands or any interests therein by inheritance or in the ordinary course of justice in the collection of debts, nor from acquiring liens on real estate or any interest therein, nor from lending money and securing the same upon real estate or any interest therein; nor from enforcing any such lien, nor from acquiring and holding title to such real estate, or any interest therein, upon which a lien may have heretofore or may hereafter be fixed, or upon which a loan of money may have been heretofore or hereafter may be made and secured. All lands so acquired shall be sold within ten years after title shall be perfected in him under said sale or the same shall escheat to the United States and be forfeited as provided in sections 1504 to 1507 of this title.