[If] two brothers, one a deaf-mute and one a competent, were married to two competent sisters, [and] the deaf-mute husband of the competent [sister] died, what should the competent husband of the [other] competent [sister] do? [Nothing, because] she is released as his wife's sister. [If] the competent husband of the competent [sister] died, what should the deaf-mute husband of the [other] competent [sister] do? He must discharge his wife with a bill of divorce, and his brother's wife is perpetually forbidden.