delivered the following opinion, affirming the judgment:
In the case of a petition for freedom, tire issue being freedom vel non, and not title to the negro, any party who may be in the possession of the negro, and who may be the party defendant to the suit, may offer any legal evidence to defeat the negro’s petition. It matters not, therefore, whether the defendant in this proceeding had been duly appointed administrator pendente lite or not, he was in the possession of the petitioners, and it was therefore competent for him to defeat, if he could, by any legal evidence, their claim to freedom. The incompetency of the grantor, from mental unsoundness, to execute a valid deed of manumission, is surely a sufficient ground to defeat such deed, and as we have said in the case of Townshend vs. Townshend, 5 Md. Rep., 287, that the question of freedom vel non, in whatever aspect it may be presented, must, by our statutes, be determined upon a petition for freedom, it follows, necessarily, that every matter which may be sufficient to defeat the petitioner’s claim, whether it be in the nature of an equitable or legal defence, can be given in evidence under a petition for freedom.
A petition for freedom is a proceeding under our statutes, and not one at common law, and therefore the principles announced in Key vs. Davis, 1 Md. Rep., 32, do not apply to such a proceeding.
From what has been said the ruling of the court upon the appellants’ first exception was a matter of no importance, and the question, however determined, could not have changed the result. We therefore decline to reverse upon this exception. Clarke vs. State, use of Darnall, 8 G. & J., 111.
It also follows that there can be no objection to the ruling of the court upon the appellants’ second exception, and we affirm it. The defendant simply proposed to show by competent witnesses, that at the date of the aforesaid deed the said *158Townshend was of unsound mind, &c. This we have said it was competent for the defendant to do upon this proceeding.
While wé are not prepared to say that in all cases evidence is admissible which tends to show unsoundness of mind subsequent to the period at which the insanity is alleged to exist, yet there are many instances where such evidence would be admissible, and this would depend very much upon the character of the insanity in question. In the case before us it will be observed, that the witness whose testimony is objected to, as disclosed in the third exception, had given evidence to which no objection had or could be taken, namely, evidence of the state of Townshend’s mind previous to, and at. the time of the execution of the deed. The record then proceeds to say, “in continuance of this witness’s testimony the defendants proposed to offer, by the same mtness, evidence of other similar conversations and acts of John Townshend subsequent to the execution of the deed of 1831, to throw light upon the state of his mind at the time of the execution of said deed.” This evidence, we think, was properly received, because it tended to show the nature and character of the insanity under which the party was supposed to labor. Tt was not the testimony of an isolated witness, which related alone to independent facts subsequent to the period involved in the issue. In such a case it might have been a question how far the acts and sayings of a party at one period, were evidence of the state of his mind at a period long anterior. But in the present case the testimony came from a witness who had known the 'party before, at the time of, and after the execution of the deed which is assailed, and the effect of this testimony was to show the state of his mind during the several periods to which it related, and that the insanity was continuing and permanent in its nature.
The question involved in the fourth exception, relating 1o the interrogatory propounded to Dr. Fonerden, is not free from difficulty upon the authorities. Upon an examination of the cases it will be found, that there is considerable conflict among them. It is clear that you cannot ask a witness, an expert, his opinion, as to the state of a party’s mind, upon *159the evidence submitted to the jury. To do so would be to transfer the functions of the jury to the witness, and would permit him to decide upon the very fact at issue, and thus to control the verdict of the jury. It is equally clear, on the other hand, that you may ask such a witness his opinion upon a state of facts, hypothetically put, based upon the evidence, and this is in fact the proper way to submit such questions to a witness. In the case now before us, it is true, this rule was not strictly observed, yet we think it was substantially. The question propounded to the witness was not his opinion upon the evidence submitted. By such a question it would be left to the witness to determine what testimony he would believe and what he would reject, and the degree of weight .to be attached to each item of testimony submitted. But the question was, “upon the hypothesis that the testimony given by the witnesses in this case, &c.,is all true,” then, what would be the witness’s-opinion?
By this interrogatory, as thus put, the witness is not permitted to weigh the testimony, but is required to assume it all to be true as stated. It is virtually, as we have said, putting an hypothetical state of case to the witness from which his opinion is to be given.
While we would have preferred that the question should have been propounded strictly in the usual form, we still do not discover such error in the terms in which it was actually put, as to justify a reversal of the judgment.
We can discover no error in the fifth exception, which relates to the prayer granted by the court. We think the legal propositions therein contained are substantially correct.
Whatever may be said about the propriety of allowing the deeds in this case to be taken by the jury to their room, it is clear that the depositions of the witness was properly withheld, and as the application to the court was to allow all the written evidence, including the depositions, to be taken by the jury, it was not error in the court to deny the application as thus made. Alexander vs. Jameson, 5 Binney, 238.
Judgment affirmed.
*160Le Grand, C. J., and Eccleston, J.,delivered the following separate opinion:
We concur in the affirmance of the judgment, and with our brother Mason in the affirmance of the ruling of the court below, as stated in the first exception, but not for the reason given by him. We think the letters were some proof in the case, and it was for the defendant to determine the order in which he would present his evidence. Plank Road Co. vs. Bruce, 6 Md. Rep., 464.