§6. It is the business of a _grand jury_ to inquire concerning crimes and misdemeanors committed in the county; and if there appear just grounds of accusation against any person, they make to the court a presentment or formal charge against him, upon which he is to be put upon trial. The number of grand jurors is not always the same. In some states there may not be more than twenty-three nor less than twelve. It is not required that they shall all agree in order to put a person upon trial. §7. On the opening of the court, the grand jurors are sworn to make a true presentment of all things given them in charge. The judge then gives them a charge, and appoints one of them foreman; and the jurors retire to a private apartment to attend to their duties. They hear all complaints brought before them against persons for crimes and breaches of the peace, and examine witnesses who appear to testify; and when it is requested, they have the assistance and advice of the state's attorney; or as he is called in some states, the _district attorney_, or _prosecuting attorney_. If they think any person complained of ought to be tried, they draw up a writing, in which they charge him with the offense of which they think him guilty. This is called an _indictment_. It is signed by the foreman, indorsed "a true bill," and carried by the jury into court. If the person accused has not before been arrested, he may now be arrested, and put upon trial. (See Chap. XVIII, §12-14.) §8. As grand juries do not try crimes, but merely make inquiry into them, some may not readily perceive the necessity of such juries. Innocent persons might be subjected to great inconvenience and expense in defending themselves in court against the slanderous reports or false accusations of evil minded persons. It is to prevent this that grand juries are instituted, who make careful examinations into the cases brought before them, and do not often charge persons with crime unless there is a strong probability of their being found guilty on trial. §9. So important was the institution of grand juries considered, that the constitution of the United States, to which the constitutions and laws of the states must conform, was made to provide, that "no person shall be held to answer for a capital or other infamous crime, unless on a presentment or indictment of a grand jury," except in certain cases. (Con. U.S., Amend. Art. V. For the definition of "infamous crime," see Chap. VI., §7.)