Existing in possibility but not in act; naturally and probably expected to come into existence at some future time, though not now existing; for example, the future product of grain or trees already planted, or the successive future instalments or payments on a contract or engagement already made. Things having a “potential ex- istence” may be the subject of mortgage, as POTEST QUIS RENUNCIARE 921 POURPRESTURE signment, or sale. See Campbell v. Grant Co., 30 Tex. Civ. App. 041, 82 S. W. 790; Dickey v. Waldo, 97 Mich. 25.”., 50 N. W. 008, 23 L. It. A. 449; Cole v. Kerr, 19 Neb. 553, 20 N. W. 598; Umg v. Mines. 40 Kan. 220, 19 Pac. 790. 10 Am. St. Rep. 192. Potest qiiis rcnunciare pro se et suis juri quod pro se introductum est. Bract 20. One may relinquish for himself and his heirs a right which was introduced for his own benelit.