2. In general, all persons may be testators. But to this rule there are various exceptions. First, persons who are deprived of understanding cannot make wills; idiots, lunatics and infants, are among this class. Secondly, persons who have understanding, but being under the power of others, cannot freely exercise their will; and this the law presumes to be the case with a married woman, and, therefore, she cannot make a will without the express consent of her hushand to the particular will. When a woman makes a will under some general agreement on the part of the hushand that she shall make a will, the instrument is not properly a will, but a writing in the nature of a will or testament. Thirdly, persons who are deprived of their free will cannot make a testament; as, a person in duress. 2 Bl. Com. 497; 2 Bouv. Inst. n. 2102, et seq. See Devisor; Duress; Feme covert;, Idiot; Influence; Parties to Contracts; Testament; Wife; Will.