Reese, C. J.
This is the second time this case has been presented to this court. The opinion upon the former hearing is reported in 90 Neb. 390, where the material facts presented by the evidence on the part of the state are quite fully stated, and need not be here repeated. After the cause was remanded to the district court, the venue was changed to Thurston county, where a trial was had, and. the cause submitted to the jury on practically the same evidence on the part of the state as at the former trial. The jury returned a verdict finding plaintiff in error, who will hereafter be referred to as defendant, guilty of manslaughter, when the indeterminate sentence of the law was pronounced against him. He brings error to this court, assigning 290 alleged errors of the district court in connection with the proceedings and trial. The assignments are specific, and many are well founded, but it will be impossible for us to discuss them without extending this opinion tó an unnecessary and unreasonable length. Particular attention can be given to comparatively few of them.
It appears from the record, and, as shown by our former opinion, that the principal witness on the part of the state, one .Albert Eich ten camp, who testified to having-seen defendant kill his sister, Louise Flege, had testified to a different state of facts at the coroner’s inquest, the effect of which was the complete exoneration of defendant. While the witness was never arrested nor charged in any legal proceeding with the commission of the crime, there appears to have arisen a known suspicion on the part of *613some that lie might be the guilty party.. He and his relatives employed an attorney to assist in the prosecution of defendant at the preliminary trial and upon the former trial in the district court, evidently under the belief that the conviction of defendant would remove all .suspicion from Eichtencamp. The attorney appeared and took an active part in the prosecution at the two trials, and was paid for his services by Eichtencamp and his relatives. After the cause was removed to Thurston county, the state was represented by the county attorney of Dixon county and the county attorney of Thurston county, when application was made to the court for the appointment of Eichtencamp’s former attorney to assist the two county attorneys in the prosecution of the case in the approaching trial. The application was resisted upon the ground that the attorney’s former employment as a private prosecutor, employed by Eichtencamp, rendered him an improper person to have charge, or any part, in the prosecution, the purpose of which was for the protection of Eichtencamp. The attorney was called to the stand, and candidly stated his relations with Eichtencamp, which continued up to the close of the former trial, which resulted in the conviction of defendant. The objection of defendant was overruled, the appointment made, and the attorney entered upon and took an active part throughout the trial, making, to say the least, a vigorous argument to the jury, which in some respects we cannot approve. While we intend no personal reflections upon the attorney, yet we do not hesitate to say that the appointment should not have been made, and that it was prejudicial error to make it. It is impossible to conceive of an attorney, after having served Eichtencamp as he had, and for the purpose for which he had been employed, to enter upon the trial with the single purpose of impartially seeking to know the truth, protecting the rights of defendant, and seeing that they were maintained, if need be, at all hazards. Not only this court, but all courts, have so clearly stated the judicial duties of a public prosecutor as *614to leave no room for doubt as to the entire impartial attitude of a prosecutor, so as to leave no room for question upon this point. In Liniger v. State, 85 Neb. 98, we said: “Public prosecutors and peace officers owe no greater obligation to the public than to a defendant charged with crime, and they should as zealously protect the one as the other.” This being true and maintained by all courts, it must appear to the mind at pnce that the appointment of a partisan special prosecutor was not in the interest of the fair and impartial trial guaranteed by the constitution. The obligation of an attorney to his client, when once employed in a particular case or matter, can never be shaken off. It is a perpetual obligation which abides to the end of life, unless, in a proper case, waived by the client. With this obligation resting upon the memory of a conscientious lawyer, as the appointee, no doubt, was and is, it would be impossible for him to forget his sworn duty to his former client, and there would be a constant inclination to ask of himself, “What effect will this evidence, or argument, have upon the rights of my first client, to whom I am still bound by every principle of law and honor? I should be faithful to my trust and protect Eichtencamp in every way possible. If defendant is convicted, Eiclitencamp is forever cleared of the suspicion resting against him.” We are forced to the conclusion that no honest and conscientious attorney could be able, nor should he, if he could, withstand such an appeal.
Error is assigned upon the ruling of the court wherein certain jurors Avere challenged for cause Avhile being examined upon their voir dire as to their competency and qualification as such jurors. John D. Girardot was called as a proposed juror. His examination is of too great length to be set out in full. He testified that he had read of the case from the time of the murder to the time of being called as a juror, and had in the meantime conversed with his family and others about it; that he was “real certain’-’ that he had formed an opinion as to the guilt or innocence of the defendant; that probably it Avas more of *615an impression than an opinion; that, if selected as a juror, he would try to give the defendant a fair and impartial trial; that the reports which he read in the newspapers published the testimony of the witnesses, all of which he read, consisting of a couple of columns each day, and upon which he formed an opinion, which he yet retained, and which Avould take strong evidence to remove; that he could not lay aside that opinion without some reason for it and evidence to cause the change; that he was afraid he could not lay that opinion aside until he had some evidence to change it. “Q. You think evidence might change it, do you? A. Yes; good, strong evidence I reckon would change it.” The juror was challenged for cause, the challenge overruled, and the juror excused on defendant’s peremptory challenge.
August Linclgrand, another proposed juror, testified that he had read the published testimony of the witnesses who were examined at the former trial “from beginning to the end,” and upon that evidence he formed an opinion as to the guilt or innocence of the defendant; that he had never changed that opinion; that it would take considerable evidence to change it, as it was a fixed opinion; that he would have to have “a pretty good reason” for changing his mind. He was challenged for cause, the challenge overruled, and the juror excused on a peremptory challenge.
J. W. Twyford, another proposed juror, testified that he read the Sioux City Journal, which published daily reports of the evidence and the testimony of .the witnesses at the former trial, which he read, and upon which he formed an opinion of the guilt or innocence of the defendant, and which he would not change until he had some reason for changing it. He Avas challenged for cause by the defendant, the challenge overruled, and the juror excused on defendant’s peremptory challenge.
Wilson W. Waters, upon his examination, testified that he had read the reports of the former trial and the testimony of the witnesses in the Sioux City Journal, on Avhich *616lie formed an opinion as to the guilt or innocence of the defendant; that he retained that opinion, could not change it without having some reason to change it, certainly would not; that in his present state of mind, if retained as a juror, if no evidence was introduced his verdict would be guilty, resting upon the opinion which he then had, and would continue to believe him guilty until he had sufficient evidence to change his mind, Avhich he could not do until he had evidence to cause the change. The defendant’s challenge for cause was overruled, the juror retained, and he signed the verdict of the jury as foreman.
Thomas Conley, examined on his voir dire, testified that during the former trial the testimony of the Avitnesses was published in the papers, and that he read the testimony, and upon that he formed an opinion as to the guilt or innocence of the defendant, deciding the case in his own mind; that he had never had any occasion to change his mind since that time, and had that opinion still; that it was a definite opinion to a certain extent; that he could not lay that opinion aside before hearing the evidence; that it would be impossible to divest himself of that opinion without hearing the evidence; that, if accepted as a juror, he would enter upon his duties Avith that opinion in his mind, and it Avould require evidence to remove it. The juror Avas challenged for cause, the challenge overruled, and he was excused on defendant’s peremptory challenge.
Exceptions Avere taken to the ruling in each case. Counsel for the state examined each juror at length, as also did the court, when they testified that they thought they could render a fair and impartial A^erdict without reference to the opinion thus formed. The defendant exhausted all his peremptory challenges, being required to deplete the number to which he was entitled by laAv by challenging the incompetent jurors. The jurors seemed to be candid and conscientious in their answers; but the fact that they so ansAvered Avas not enough to render them competent.
It is provided in section 468 of the criminal code: “The *617following- shall be good canses for challenge to any person called as a juror on the trial of any indictment: * * * 2d. That he has formed or expressed an opinion as to the guilt or innocence of the accused; provided, that if a juror shall state that he has formed, or expressed, an opinion as to the guilt or innocence of the accused, the court shall thereupon proceed to examine, on oath, such juror as to the ground of such opinion; and if it shall appear to have been founded upon reading newspaper statements, communications, comments, or reports, or upon rumor, or hearsay, and not upon conversations with witnesses of the transactions, or reading reports of their testimony, or hearing them testify, and the juror shall say, on oath, that he feels able notwithstanding such opinion to render an impartial verdict upon the law and the evidence, the court, if satisfied that said juror is impartial, and will render such verdict, may, in its discretion, admit such juror as competent to serve in such case.” It will be readily seen that, where the opinion is formed from “reading reports of their (the witnesses) testimony,” the juror does not come within the proviso, and is incompetent, without reference to what he may say as to his ability to render an impartial verdict, or what influence his preconceived opinions might have upon his judgment in weighing the evidence.
In Carroll v. State, 5 Neb. 31, we held that, if it appear that the juror has formed an opinion from reading reports of testimony of witnesses, he is incompetent, although he may be willing to swear that, notwithstanding such opinion, he feels able to render an impartial verdict, and the judgment was reversed solely upon the one ground with reference to but one juror,
In Curry v. State, 4 Neb. 545, it is said: “We think it is clear that where the ground of challenge’is the formation, or expression, of an opinion by the juror, before the court can exercise any discretion as to his retention upon the panel, it must be shown by an examination of the juror, on his oath, not only that his opinion was formed *618solely in the manner stated in this proviso, hut, in addition to this, the juror must swear unequivocally” to his ability to render a fair and impartial verdict upon the 1 aw and evidence. As an opinion formed from reading the report of the testimony of the witnesses is excluded from the proviso, it is as clear as the English language can make it that the district court had no discretion in the matter whatsoever, but its plain duty was to sustain the challenge. The jurors were wholly incompetent. Such has been the plain provision of the statute since the early days of the judicial history of the state, and the courts have recognized its binding force. Why the statute Avas ignored is not a question with which we have to deal. The constitution guarantees to every man a fair trial by an impartial jury. That a juror could be considered impartial, who had read the eAddence of the witnesses on a former trial, and formed an abiding opinion thereon, and could by any effort on his part disrobe himself of that opinion, is not within the reach of human nature, and lienee the statute absolutely disqualifies him. See Smith v. State, 5 Neb. 181.
The defendant exhausted his peremptory challenges, and therefore did not waive his constitutional and statutory rights. Thurman v. State, 27 Neb. 628; Kennison v. State, 83 Neb. 391; Brinegar v. State, 82 Neb. 558; State v. Brown, 15 Kan. 400.
During the introduction of the testimony, the state offered in evidence the clothing worn by the decedent at the time of her death, consisting of her dress, chemise, sun-bonnet and apron, in their soiled, burnt and bloody condition. Those exhibits Avere objected to by the defense as incompetent, irrelevant and immaterial, not tending to establish any issue or fact in the case, nor tending to prove defendant’s guilt, but only for the purpose of inflaming the jury. The objection was overruled, the garments, admitted in evidence over defendant’s exceptions, were displayed and'held up before the jury. Error is assigned upon this ruling. There are, no doubt, many in*619stances in which there is no error in the admission of such articles in evidence. Sometimes it becomes necessary for the state to prove the proximity of the firearm to the wound made by the ball, and this may be done by showing the burnt condition of, or powder stains upon, the clothing. In other cases it may be necessary to prove the relative locations of the victim and person using the firearm. This may often be shown by the range and course of the ball in passing into or through the clothing and body of the decedent. It is also permissible if it tends to prove the identity of the person killed, or of the slayer. Rut some necessity for this class of evidence should appear to justify its admission. This involves the exercise of discretion on the part of the trial court. There is nothing in the record showing that the exhibition of the bloody and burnt garments was a proper, or necessary, part of the state’s case. The court adheres to the holding in McKay v. State, 90 Neb. 63, 91 Neb. 281, that if it appears that the introduction of the blood-stained garments was for the purpose of arousing the passions of the jury, arid by that means securing a conviction, the practice should be condemned and a judgment of conviction reversed. Unless it appears that the offered evidence would be material to some inquiry in the case on trial, such exhibits should be excluded. See Cole v. State, 45 Tex. Cr. Rep. 225, 75 S. W. 527; Christian v. State, 46 Tex. Cr. Rep. 47, 79 S. W. 562; Melton v. State, 47 Tex. Cr. Rep. 451, 83 S. W. 822; Williams v. State, 61 Tex. Cr. Rep. 356, 362, 136 S. W. 771; Lucas v. State, 50 Tex. Cr. Rep. 219, 95 S. W. 1055. In 2 Wharton, Criminal Evidence (10th ed.) sec. 941, it is said: “As clothing is in the nature of demonstrative evidence, it has a strong tendency to arouse feelings of prejudice or passion, and unless the articles so introduced serve the purpose of identifying the deceased, or of honestly explaining the transaction, the introduction is irrelevant, and constitutes prejudicial error; and particularly is this true when it,is displayed in such manner as to arouse prejudice and passion.”
*620On the part of the defense, Dr. Meis, of Sioux City, Iowa, Professor Walter S. Haines, of Rush 'Medical College, Chicago, and Professor Ludvig Hektoen, of the same place, were called as expert witnesses. It is shown beyond dispute or contradiction that, at or about 12 o’clock on the day of the homicide, the decedent ate her usually hearty dinner, consisting of a variety of food. If the testimony of Eichtencamp is true, she was slain about one hour thereafter, or about 1 o’clock P. M. A post mortem examination was had some time that evening or early the next morning. The body was embalmed and buried. Some considerable time thereafter, a number of months, the body was exhumed and found to be in a good state of preservation, the stomach removed, and the contents sent to Professor Haines for analysis. It was agreed by all that the wound in the head would, and did, produce instantaneous death. The experts testified that at death all digestion of food taken into- the stomach immediately ceased. The analysis disclosed that the contents of the stomach were quite thoroughly digested, and it was shown that digestion would scarcely be commenced within one hour after eating, that it could not be advanced to the extent shown short of two and one-half to three hours thereafter, and therefore it was insisted that it was impossible that decedent could have been killed within one hour after eating the noon meal. The testimony of all the witnesses on that part of the case agrees that, about 1 o’clock on the day of the homicide, the defendant left his home, and did not return until late in the afternoon, and after the discovery of the body of the decedent. After a somewhat careful examination by questions and answers, certain hypothetical questions were asked and answered by which the testimony of the experts was further elucidated. We have examined the evidence with care, and are unable to discover where the hypothetical questions varied in any material degree from the testimony, and especially from the evidence and theory of the defense. The experts, were men of high standing in their profession *621and. of known probity of character. In instructing the jury, the court gave the fifteenth instruction, as follows:
“You are not to take for granted that the statements contained in the hypothetical questions which have been propounded to the witnesses are true. Upon the contrary, you are to carefully scrutinize the evidence, and from that determine what, if any, of the averments are true, and what, if any, are not true. Should you find from the evidence that some of the material statements therein contained are not true, and that they are of such character as to entirely destroy the reliability of the opinions based upon the hypothesis stated, you may attach no weight whatever to the opinions based thereon. You are to determine from all the evidence what the real facts are, and whether they are correctly or not stated in the hypothetical question or questions. I need hardly remind you that an opinion based upon a hypothesis wholly incorrectly assumed, or incorrect in its material facts, and to such an extent as to impair the value of the opinion, is of little or no weight. Upon the matters stated in these hypothetical questions, and which are involved in this investigation, you are to give the defendant, the benefit of all reasonable doubt, if any there should be, and where there is a reasonable doubt as to the truth of any one of the material facts stated, resolve it in the defendant’s favor.”
As an abstract proposition of law, this instruction may be, in the main, unobjectionable, and might be properly given in a case to which it should be applied, but we are unable to see whére or how it could have any just application to this case. As a general rule the principle involved in this instruction is recognized as applying to the testimony of experts upon questions in which most people have what might be denominated common knowledge, and when such testimony is presented to the jury, or other trier of fact, who may have opinions of their own derived from common experience and observation; and, if an expert gives an opinion which is at variance with that common knowledge or ex*622perience, the juror is allowed, to make use of Ms own knowledge, intelligence and judgment in weigliing the testimony of the expert. But tMs rule does not apply in its entirety where tlie substance of the testimony is upon a subject not understood or known by the layman, and the testimony is confined to purely scientific investigations and close application with which others than those making the investigations have no knowledge. As said by Judge Taft in Ewing v. Goode, 78 Fed. 442: “In many cases, expert evidence, though all tending one way, is not conclusive upon the court and jury, but the latter, as men of affairs, may draw their own inferences from the facts, and accept or reject the statements of experts; but such cases are Avhen the subject of discussion is on the border line betAveen the domain of general and expert knoAvledge, as, for instance, where the value of land is involved, or Avhere the value of professional services is in dispute. There the mode of reaching conclusions from the facts Avhen stated is' not so different from the inferences of common knowledge that expert testimony can be anything more than a mere guide. But when a case concerns the highly specialized art of treating an eye for cataract, or for the mysterious and dread disease glaucoma, Avith respect to which a layman can have no knowledge at all, the court and jury must depend on expert evidence. There can be no other guide.”
It cannot be denied that the question of post mortem digestion is one upon which the great majority of people have never thought and have no information whátever. This want of knowledge is not confined to laymen. It involves long, careful, patient and persistent investigation, and comparatively few have given the subject sufficient thought .or investigation to enable them to speak with anything like exact knowledge thereon. As said in the quotation above given, there can be no other guide than the knowledge of those who have made the subject a matter of special study. True, the jury may bring to their aid such knowledge and experience as they may have *623upon the subject in hand, but, in the absence thereof, they would not be justified in ignoring the testimony of fully qualified experts. The subject is one which the layman, the lawyer, the judge, and even the physician, is not called upon to investigate as fitting him for his profession or station in life. It is safe to say that not one person in thousands has given the subject any investigation or thought. Courts and jurors are usually totally in the dark thereon, and must depend upon the researches of those who have made the subject one of special investigation and upon which they are qualified to give correct opinions. The expert witnesses were men of known competency and standing in their profession, and upon such the courts must, to a great extent, depend for their guidance when considering questions of the kind under consideration. It must also be observed that, as shown by the bill of exceptions, much the greater portion of the testimony of the experts was not given upon hypothetical questions, but upon direct questions containing no statement of facts, hypothetical or otherwise, to which they responded by the statement of facts resulting from their researches and investigations. The instruction is almost a literal copy of one given in the trial of Guetig v. State, 66 Ind. 94, wherein the instruction was approved. In that case the question of the insanity of the accused presented the principal defense. The difference in the quality of the subjects under investigation must be apparent to every thinking mind. On the question of the sanity of an individual the inquiry is not limited to the testimony of expert witnesses, but the nonexpert, who has observed the conversation, conduct and bearing of the accused, is as competent to testify as the expert. This cannot be true upon the subject of post mortem digestion. Upon this subject no one but the expert is qualified to testify at all. As said in Lawson, Expert and Opinion Evidence (2d ed.) 285: “It is safer, on the whole, to trust to the judgment of learned men, acquired by study, observation and skill, than to the imperfect deductions of jurors, hastily *624derived from readings not familiar to them, unassisted by study, examination and comparison of kindred subjects. * * * Great respect should be accorded to the views of such a class of witnesses.” It must appear to any thinking mind that the instruction was too general, as applying to all cases, and a regard to the due administration of justice Avould require greater care and discrimination in an instruction upon a question of this kind.
By the sixteenth instruction the jury are permitted to “accept or reject such opinions, as you may accept as true, or reject as false, any other facts in the case. The jury are instructed that the opinions of the witnesses as experts are merely advisory and are not binding on the jury, and the jury should accord to them such Aveight as they believe, from the facts and circumstances in evidence, the same are entitled to receive.” The testimony of the experts explained to the jury the process of digestion, the combination of gases and acids which entered into the process, the necessity for vital action in order that the fluids be secreted by- the stomach, but which instantly ceased upon death. All this was carefully stated and explained, without contradiction or dispute, and which the very nature of the testimony would naturally convince the minds of the jury of its truth, yet the jury were informed that they might ignore it all, without a syllable of evidence calling it in question, and, necessarily, Avithout any knoAVledge or experience on their part by Avhich it might be compared or tested. The jury evidently took the court at its word and arbitrarily cast the proof aside as not worthy of belief.
In the twenty-third instruction the jury were informed that defendant denies the killing of the decedent, and claims that she Avas not killed until after he left his home on the day of the homicide; “and, if you believe the defendant not guilty, and that he did not shoot and kill the said Louise Elege, as alleged in the information, or in the event that the evidence introduced in the case is so evenly balanced that you cannot tell whether defendant or some *625other person shot and killed the deceased, as alleged, then yon should acquit the defendant, or if you entertain any reasonable doubt of the guilt of the accused of the crime charged in the information then you should give the defendant the benefit of such doubt and acquit him.” This instruction is objectionable in several particulars: First, if the jury believe the defendant not guilty, they should acquit; second, if they believe he did not shoot and kill the decedent, they should acquit him; third, if the evidence is evenly balanced, they should acquit; fourth, if they cannot tell whether defendant or some other person committed the crime, they should acquit; or fifth, if they have any reasonable doubt of his guilt, they should acquit. We know of no rule of law that requires the jury to “believe the defendant not guilty,” or that he “did not shoot and bill” the decedent, before they could acquit. The burden is on the state to prove his guilt beyond a reasonable doubt, and this part of the instruction, as well as others, except the last clause, should not have been given. It could only confuse the jury, and possibly cause them to believe that they must “believe” him “not guilty,” and believe he “did not shoot and kill” decedent, before they could acquit.
In the twenty-sixth instruction the jury were again informed that “if you find that he did not shoot the said Louise Flege, or entertain a reasonable doubt of- his guilt, you should acquit him.” Here is a repetition of the same vice. It was not necessary that the jury should find that he did not commit the deed. The question to be decided Avas: Has the state proved beyond a reasonable doubt that he did?
A sharp criticism is made against the conduct of counsel for the state in the closing argument to the jury, but, as that attorney will appear no further in the case, the contention need not be further considered. There is also complaint as to the conduct of other counsel for the state.. As it is hardly probable that the objectionable language, Avhich Ave need not specify, will be repeated on another *626trial, it is thought that it need not be further noticed, Prosecuting officers should always remember that it is not so much their duty to secure convictions as to present the truth without indulging in crimination or recrimination or personal abuse of an accused. If unjust practice is indulged in, the court should repress all such efforts with a firm hand. The constitution and laws guarantee to every person a fair trial. It is the duty of the courts to see that this guaranty is fulfilled. People v. Davenport, 13 Cal. App. 632, 110 Pac. 318; 12 Cyc. 571; McKay v. State, 90 Neb. 63, 74; Nickolizack v. State, 75 Neb. 27, 32; Wilson v. State, 87 Neb. 638, 649; Leahy v. State, 31 Neb. 566; State v. Irwin, 9 Idaho 35, 60 L. R. A. 716; Bailey v. People, 130 Pac. (Colo.) 832.
The judgment of the district court is reversed and the cause remanded.
Reversed.