Brokers are often called as witnesses in trials to give testimony as to values of property, situation, character, and surroundings of property, etc., and the question arises whether the broker is in such cases entitled to more than the ordinary witness fees. If the broker's services consist entirely of testifying at the trial to facts within his knowledge, then no recovery may be had by him in the absence of an express promise beyond the ordinary witness fees. But this rule does not go to the extent of obliging a person to give technical expert testimony without reasonable compensation. The law regards such knowledge as the capital of the person possessing it which a litigant has no right to utilize without paying for it. But where one voluntarily testifies on request without insisting on compensation as a condition of giving his evidence, he could hardly afterward hold the person on whose behalf he testified, to more than the ordinary witness fees. Where, however, the services for which compensation is claimed are not for the giving of the testimony but for the time and labor spent in making the necessary investigation in order to qualify him as an expert witness, such time and labor are services rendered outside and beyond services as a witness, and "it has been repeatedly held that professional persons cannot be required to make any examination or preliminary preparation in order to better qualify themselves as experts, and that when, on request, such services are performed for another, extra compensation may be demanded upon an implied promise in the absence of an express promise of compensation. The authorities holding this doctrine in various forms are numerous."14
13See Sec. 47, 59.
14Tiffany v. Kellogg Iron Works, 59 Misc. 113; 109 N. Y. Suppl. 754 (1908); citing Brown v. Travelers' Life ft Accident Ins. Co., 26 App. Div. 544: 50 N. Y. Suppl. 729; People v. Montgomery, 13 Abb. Pr. (N. S.) 207 (N. V); Schofield v. Little, 2 Ga. App. 286; 58 S. E. 666; Board of Comm. v. Lee, 3 Col. App. 177; 32 Pac. 841; Barrus v. Phaneus, 166 Mass. 123; 44 X. E. 141; 32 L. R. A. 619; Flinn v. Prairie Co., 60 Ark. 204; 29 S. W. 459; 27 L. R. A. 669; 46 Am. St. Rep. 168; St. Francis Co. v. Cummings, 55 Ark. 419; 18 S. W. 461; Summers v. State, 5 Tex. App. 365; 32 Am. Rep. 573; Ex parte Dement, 53 Ala. 389; 25 Am. Rep. 611.