Neither the state, nor a person held to answer a charge for a public offense, can take advantage of any objection to the panel or to an individual grand juror unless it be by challenge, and before the grand jury is sworn, except that after the grand jury is sworn, and before the indictment is found, the court may, in its discretion, upon a good cause shown, receive and allow a challenge.
R.L.1910, § 5705.