It has been a matter of grave discussion whether an expert is bound to testify on matters of opinion without extra compensa tion, the weight of decisions being that he is not bound to do so ; 1 C. & K. 25; Ex parte Roelker, Sprague 276, Fed. Cas. No. 11,995 ; Dills v. State, 59 Ind. 15 ; Clark County v. Kerstan, 60 Ark. 508, 30 S. W. 1046 ; contra, Ex parte Dement, 6 Cent. L. J. 11; U. S. v. Cooper, 21 D. C. 491; Buchman v. State, 59 Ind. 1, 26 Am. Rep. 75 ; Dills v. State, 59 Ind. 15; 6 So. Law Rev. 706. In the absence of statutory authority, an expert for the state cannot demand extra compensa tion, at least when not compelled to make any preliminary examination or preparation, or to attend and listen to the testimony ; Flinn v. Prairie County, 60 Ark. 204, 29 S. W. 459, 27 L. R. A. 669, 46 Am. St. Rep. 168 ; and when no demand is made in advance for special compensation, he can recover only the statutory witness fees ; Board of Com'rs of County of Larimer v. Lee, 3 Colo. App. 177, 32 Pac. 841; Tiffany v. Iron Works, 59 Misc. 113, 109 N. Y. Supp. 754. When an ex pert is required to make a preliminary ex amination or to prepare specially for his tes timony, he is allowed extra compensation in addition to the ordinary witness fees ; Kel ler v. Harrison, 151 320, 128 N. W. 851, 131 N. W. 53, Aun. Cas. 1913A, 300 ; Gordon v. Conley, 107 Me. 286, 78 Atl. 365, 33 L. R. A. (N. S.) 336; Burnett v. Freeman, 125 Mo. • App. 683, 103 S. W. 121; Schofield v. Little, 2 Ga. App. 286, 58 S. E. 666 ; Philler v. Waukesha County, 139 Wis. 211, 120 N. W. 829, 25 L. R. A. (N. S.) 1040, 131 Am. St. Rep. 1055, 17 Ann. Cas. 712 ; and it has been held that a physician testifying as an expert comes within such rule; People v Board of Sup'rs, 148 App. Div. 584, 132 N. Y. Supp. 868; but usually a physician is required to give expert testimony without extra compen sation ; People v. Conte, 17 Cal. App. 771, 122 Pac. 450, 457 ; State v. Bell, 212 Mo. 111, 111 S. W. 24 Chicago St.• R. Co. v. Zeiger 78 Ill. App. 463, affirmed in 182 111. 9, 54 N. E. 1006, 74 Am. St. Rep. 157; especially when the physician is attending professionally one of the parties ; Anderson v. Ry. Co., 103 Minn. 184, 114 N. W. 744; Burnett v. Freeman, 134 Mo. App. 709, 115 S. W. 488. It is held that an expert who testifies on a subject re quiring special knowledge and skill is en titled only to the statutory fee ; Main v. Sherman County, 74 Neb. 155, 103 N. W. 1038 ; and so where a witness had knowledge common to persons in a particular neighbor hood, not based on study or investigation, and in spite of a special contract for extra compensation ; Ramschasel's Estate, 24 Pa. Super. Ct. 262. Expenses of expert witnesses cannot be allowed as between the parties at a rate exceeding the usual fees ; [1900] 1 Ir. Rep. 22 ; Randall v. Journal Ass'n, 22 Misc. 715, 49 N. Y. Supp. 1064 ; Linforth v.
Gas Co., 9 Cal. App. 434, 99 Pac. 716.
Under equity rule 48 (S. C. of U. S., in effect Feb. 1, 1913, 33 Sup. Ct. xxxi), the dis trict court, in a case involving the scope or validity of a patent or trade-mark, may, up on petition, order that the examination in chief of the experts be set forth in affida vits and filed: Those of plaintiff within 40 days after the cause is at issue ; those of de fendant 20 days after plaintiff's time has expired ; and rebutting affidavits 15 days after the time for filing the originals ex pired. The court or a judge may direct the cross-examination and any re-examination before the court at the trial. If the expert be not produced, the affidavit shall not be used.
A statute providing for the appointment of expert witnesses by the court without notice to the respondent or prosecuting attorney in cases of homicide was declared unconstitu tional in People v. Dickerson, 164 Mich. 148, 129 N. W. 199, 33 L. R. A. (N. S.) 917, Ann. Cas. 1912B, 688.
In Germany expert witnesses are appoint ed by the court and are regarded as assist ants to the trial judge. The judge decides whether they shall be called or not; he may inform himself from other sources upon the questions raised. There are lists of experts made under local laws ; they are usually nominated by the various trades and pro fessions. They are sworn in and need not be sworn in the particular case. If the par ties have agreed upon an expert, he must be examined together with others designated by the judge if he so desires.
Frequently the experts furnish a written opinion and are not examined. The rules are the same in civil and criminal cases.
In Prance in civil cases each court selects expert witnesses and publicly announces their names. They are classified under 49 different categories. Usually three are ex amined ; but the parties may agree to exam ine only one. If the parties cannot agree within three days on their choice of the ex perts to be called, the court appoint. They report in writing signed by all. If they dif fer in opinion, the grounds of difference must be stated, but not the name of the dis sentient. The report need not be sworn to.
In criminal cases the experts are selected by the procureur (district-attorney) or they may be called by the examining magistrate or the trial judge.
Lists of experts of various professions are published by the official registrars of the courts and are appointed by the minister of justice with the advice of the presidents of the courts and the district attorney. They are entitled to ask for any fee they consider due for their services, there being no fixed schedule. Each profession is considered on its merits. Sometimes an expert not on the list may be selected by, the judge. The rule that there must be an uneven number of ex perts does not apply in the criminal courts.
See OPINION; PATENT; HYPOTHETICAL QUESTION.