It has been seen that one who, under circumstances raising a moral duty, voluntarily discharges another's obligation, may recover in quasi contract for the benefit thereby conferred (ante, Sec. 193 etseq.). A fortiori, one is entitled to recover when such discharge of another's obligation is compelled by law. The compulsion may result either from the fact that the plaintiff's property is subject to sale or his interests are prejudiced in case the defendant's obligation is not performed, or from the fact that the plaintiff is himself legally bound to perform the duty which, as between the plaintiff and the defendant, rests in equity and good conscience upon the latter. The benefit to the defendant is not less real because it consists of a saving of expenditure rather than an addition to his estate (ante, Sec. 8).