[181] The conservatism of lawyers is proverbial. It is hard to convince them that forms that have been long in use and have been found to serve a useful purpose in the past, are not applicable to new conditions as they arise; for instance, that the methods of procuring the attendance and of examining ordinary witnesses do not fit the necessities of expert testimony. But the question as to the defects of the system as it now exists has been brought to public attention in the journals of the day, in papers read before medical societies and bar associations, and in arguments in legislative bodies, and it is hoped and believed that ere long a reform, something of the character indicated, may be brought about in this very important matter.
[182] It has been a matter of great discussion whether an expert is compellable to testify on matters of opinion, without compensation, the weight of the decisions being that he is not bound to do so. 1 Greenleaf on Evidence, § 310; 1 Warwick Law Assizes, 158; Parkinson v. Atkinson, 31 L. J. (n. s.) C. P., 199; Webb v. Page, 1 E. & K., 25; People v. Montgomery, 13 Abb. Pr., n. s., 207; Ex parte Roelker, 1 Sprague, 276; Buchanan v. The State, 59 Ind., 1; Dills v. The State, Id., 15; U. S. v. Howe, 12 Cent. L. J., 193; contra, 6 Central Law Journal, 11; Ex parte Dement, 53 Ala., 389; Sumner v. The State, 5 Tex., 21; 6 Southern Law Review, 706.; and see generally Wharton on Evidence, sec. 380, note 66, sec. 456; Lawson on Expert and Opinion Evidence; Rogers on Expert Testimony. As to the compensation being paid before the testimony is given, see Wharton on Evidence, secs. 456, 380; People v. Montgomery, 13 Abb. Pr., n. s., 207.
It is proper, although not necessary, that upon cross-examination the witness should be asked as to his fee; that is, as to whether he expects to receive any additional fee besides that of an ordinary witness, and it has been held that where the expert witness testified that he was to receive a fee which was contingent upon the case, he was disqualified from testifying. Pollock v. Gregory, 9 Bosworth, N. Y. Superior Ct. Rep., 121-124.
[183] This latter case holds that a second expert may be called to testify after the first has been thus challenged, to support his capacity and skill. The contrary rule, however, obtains in Alabama (Tellis v. Kidd., 12 Ala., 643; Pugh v. State, 44 Ala., 33). Neither can an expert be contradicted by books of science; that is, by books of science introduced in evidence as such (Wharton on Evidence, 666, 721). This is so because the rule is well established that books, although of great authority in themselves, may not, even if proven to be such, be placed in evidence. They may, however, be read to the witness, and so be placed upon the record, passage by passage, and the witness may be asked whether he agrees with that doctrine, not, however, as part of his direct examination, but as part of his cross-examination.
A medical expert is sometimes confronted upon the witness-stand by long quotations from well known medical text-books, and he is asked whether the doctrines, opinions, etc., there laid down are sound. Especially is this done when such doctrines and opinions are in apparent discord with his evidence as he gives it. In such cases as this, however honest, however intelligent and non-partisan the witness may be (except as any opinion on one side or the other of a disputed question may be considered partisan), he is placed in a very difficult position. If the citations and questions are from well-known authors, and he is a modest man, as most men of learning are, it will be difficult for him to deny that such authorities as these have great weight, even more weight than his experience, skill, and knowledge entitle him to claim. On the other hand, if he takes the bold course and sticks to his opinion, he is cried down the winds by counsel in summing him up, as a man of gall, boldness, audacity and egotism. His course is difficult whichever way he turns, but modesty as well as honesty is usually the best policy. Perhaps the best thing for such a witness to do under such circumstances is to do as once did the great mental alienist Dr. John P. Gray, when, having given an opinion on a question of insanity, he was cross-examined as to the different theories from time to time prevalent as to what insanity was, and having stated what theories were then the accepted ones, he was confronted by counsel on his cross-examination with the question: “What do you think of Dr. John P. Gray as an authority on that question?” and then with his own writings, quite extensive, of many years before, in which he had advocated theories apparently different from those which he had professed upon the witness-stand. Placed in this position, the distinguished gentleman simply replied: “It is true I cherished those theories at that time, but I lived to learn better,” thus substantially disarming any criticism that could be made of him in his capacity as a witness in that case.
[184] For general rules for the conduct of expert witnesses see infra.
[185] The principal classes of such subjects may, however, be briefly stated as follows:
1. Causes of death; especially in cases of homicide, suicide, accident, etc., including poisoning.
2. Causes, nature, and extent of personal injuries, by violence, accidents, explosions, railway disasters, collision between vessels, etc.
3. Birth of infants; was infant born dead or alive; if dead, was death the result of natural causes or of internal violence; age of infant at the time of birth or death. Also causes of alleged sterility or pregnancy; time pregnancy has existed; also cases of alleged impotency.