Wills can be revoked in whole or in part, only by being canceled or destroyed by the act or direction of the testator with the intention of so revoking them, or by the execution of subsequent wills. [§3529.] The birth of a child after the execution of a will but before the death of the testator, operates as a revocation of the will, and the birth and recognition of an illegitimate child has the same effect. Declarations of the testator to the effect that he intended to revoke the will, will not be sufficient to prove a cancellation. [Sidenote: Cancellation.] When done by cancellation, the revocation must be witnessed in the same manner as the making of a new will. [§3530.] [Sidenote: Executors.] If no executors are named in the will, one or more may be appointed to carry it into effect. [§3532.] [Sidenote: Posthumous children.] Posthumous children unprovided for by the father's will, shall inherit the same interest as though no will had been made. [§3534.] [Sidenote: Heirs of a devisee.] If a devisee die before the testator, his heirs shall inherit the amount so devised to him unless from the terms of the will a contrary intent is manifest. [§3537.] The word heir in this section does not include the widow of the testator, and she cannot inherit from a child to whom property has been devised by his father, but who has died before the father. [Sidenote: Married women.] A married woman may act as executor independent of her husband. [§3545.] [Sidenote: Minors.] If a minor under eighteen years of age is appointed executor, there is a temporary vacancy as to him until he reaches that age. [§3546.] [Sidenote: Administration. Who entitled. Order.] In other cases where an executor is not appointed by will, administration shall be granted: 1. To the wife of the deceased; 2. To his next of kin; 3. To his creditors; 4. To any other person whom the court may select. [§3555.] [Sidenote: Classes united.] Individuals belonging to the same or different classes, may be united as administrators whenever such course is deemed expedient. [§3556.] [Sidenote: Time allowed.] To each of the above classes in succession a period of twenty days, commencing with the burial of the deceased, is allowed within which to apply for administration upon the estate. [§3557.] CHAPTER VIII. SETTLEMENT OF THE ESTATE--DESCENT AND DISTRIBUTION OF PROPERTY. [Sidenote: Exempt personal property.]