1. It would have been irregular to stop the trial, for the purpose of substituting a juror in the place of Weakly, even if the opinion formed by him, had ever been expressed. The prisoner was not deceived; for he knew from the previous examination of the juror, that some opinion had been formed by him, and might have challenged peremptorily. Instead of doing this, he accepts the juror, who is sworn in chief. All the authorities concur in the opinion, that when a juror is once sworn, he cannot be afterwards challenged for a cause which existed at the time when he was put on the prisoner. (Chitty’s Criminal Law, 444, and cases there cited ; Yelverton 24; Williams v. The State, 3 Stew. 454.)
2. 3. If this matter had been disclosed at the time of swearing the juror, it would not have availed the prisoner as a cause of challenge. The opinion, whether in favor of, or against the prisoner, was never expressed, and for this reason alone, it may be questionable, whether either the State or the prisoner, could challenge for cause. But which ever way the bias of the juror may have been, it was clearly formed from mere rumor, because Lee, from whom his information was derived, had no knowledge ©f the facts attending the homicide, and when called as a witness, was to give testimony of his opinion as a physician, upon the facts detailed by others.
4. Some doubt seems to have been heretofore felt, whether this Court is not precluded from the revision of a question, when of such a description, that the action of the Circuit Court upon it, must be purely a matter of discretion.
The only limitation provided by the statute is, that the question referred, shall be novel and difficult. (Aikin’s Digest, 257, s. 16.) Previous to this enactment, the Circuit Courts, at their discretion, could respite the judgment in any criminal case, on a point reserved, motion in arrest of judgment, or for a new trial, for the- consideration of the Supreme Court. (Digest, 243, s. 22.)
The Circuit Court unquestionably has the right to require the opinion of this Court on any question, whether the judgment to *278be exercised by it is discretionary or otherwise, which arises in a criminal case, and which is considered by the presiding Judge as novel and difficult.
It is therefore, not very important to ascertain, whether the admission or rejection of an infant witness, is a matter of discretion, as distinguishable from a matter of right, and thus resting solely with the Judge trying the cause; but if it is conceded to be so, the proper exercise of that discretion, is one of the matters referred in this case. It may not be improper to add, that we incline strongly to the impression, that the admission or rejection of all evidence, is not a matter of mere discretion, but rather, that all such questions involve rights which must be ascertained, and determined, by fixed principles, and by the rules .of law. We are not aware of any adjudicated case, which tends to support Mr. Starkie in the contrary opinion, which is stated in his work on evidence, 2 vol. 393.
5. We are not certain that the reference made in this case, is as precise as it might have been; but we understand the main question to be, whether the Circuit Court was authorized to arrive at a conclusion, respecting the admission or rejection of the infant witness, from a private examination, after a public examination in Court had resulted in the exclusion of the witness, in consequence of an apparent defect of knowledge, with respect to the obligations of an oath.
In Lord Hale’s time, it was common to examine children of tender years, without swearing them. (1 Hale, P. C. 634.) This practice was overturned in 1779, in Brazier’s case, when the Judges were unanimously of the opinion, that 'no testimony whatever, could be legally received, except when given on oath; and that an infant, though under the age of seven years, might be sworn in a criminal prosecution, provided such infant appeared, on a strict examination, by the Court, to possess a sufficient knowledge of the nature and consequences of an oath ; for there is no precise rule as to the age within which infants are excluded from giving evidence, but their admissibility depends on the sense and reason they entertain of the danger and impiety of falsehood, which is to be collected from their answers to questions propounded to them by the Court; but if *279they are found incompetent they, cannot be received. (Rex v. Brazier, Leach 346; Buller’s N. P. 393.)
6. This case is a most satisfactory exposition of the law, and establishes that the Court, and not the judge, as an individual, is to be satisfied of the competency of the infant offered as a witness. It may be objected, it is scarcely possible, that an infant of such tender years, can be capable of satisfactorily answering questions amidst the bustle and confusion of a Courthouse ; but certainly the consequences would be alarming, if the admission of such a witness might be effected through the medium of a private examination; and more so, when one made in public had proved to be unsatisfactory.
We do not wish to be understood as intimating, that the precise interrogatories used in this case were necessary, or even, that only such would be proper. The competency of such witnesses depends on the sense and reason they entertain of the danger and impiety of falsehood, and if such a sense can be collected from their answers they should be admitted, otherwise rejected.
7. The remaining' question to be considered, is that which relates to the propriety of the charge, which was refused as well as that which was given.
It is conceded by the counsel of the prisoner, and properly so in our opinion, that if the death [was accelerated by the violence of the prisoner, his guilt is not extenuated, although death might be, and probably would have been the result of the disease, which then afflicted the deeéased.
8. But it is insisted that the Circuit Court, was wrong in assuming, that the prisoner was guilty of murder, when the crime, in the consideration of the jury, under the facts in evidence, may have been but manslaughter.
The evidence on which the charge was asked, is not stated but we must presume, from the absence of any request by the prisoner to modify the instructions, that they were warranted by the facts, and that their correctness in point of law was alone disputed.
The charge given to the jury, seems to be nothing more than a response to that which was requested, but refused.
*280We can perceive no other error in the decision of the several questions referred, than the admission of the infant without a satisfactory examination in open Court.
In consequence of the improper admission of this witness, the sentence must be vacated and the judgment reversed.
The prisoner to be kept in custody to await another trial, unless discharged by due course of law.