McCarthy v. Boston Duck Co.

• Decision Date: 04 January 1896
• Citation: 42 N.E. 568,165 Mass. 165
• Parties: McCARTHY v. BOSTON DUCK CO.
• Court: United States State Supreme Judicial Court of Massachusetts Supreme Court

165 Mass. 165

42 N.E. 568

McCARTHY v. BOSTON DUCK CO.

Supreme Judicial Court of Massachusetts, Hampden.

January 4, 1896

The court refused to permit plaintiff to ask an expert witness the following question: "You saw this machine, and you heard the testimony here to-day of Mr O' Connor about the way this belt was fastened,--with this Talcott plate. What do you say,--taking into account all the circumstances, its size, the shipper the way it ran, the size of the upper pulley, and the way it was fastened,--what do you say, whether or not that was a proper fastening?"

COUNSEL

J.B Carroll and W.H. McClintock, for plaintiff.

William H. Brooks, for defendant.

OPINION

FIELD C.J.

We infer that the first question put to the witness Webber was excluded by the court on account of the form of it, because, when counsel stated what he offered to show by the witness, the court said, "I have not ruled on that." The usual way of asking for an opinion of an expert is to state hypothetically the facts upon which the opinion is desired. Woodbury v. Obear, 7 Gray, 567, 571. It is said, however, that this is not an exclusive formula. Hunt v. Light Co., 8 Allen, 169, 172. It is important that the form of the question should be such as not to require or permit the witness to draw conclusions of fact from the evidence in the case, and to give an opinion based wholly or in part upon such conclusions. A witness ought never to be permitted to give an opinion upon the effect of evidence in establishing facts which do not depend upon his knowledge as an expert. Where the evidence is conflicting or relates to many details, or where inferences of fact must be drawn from the evidence, in order to be reasonably certain of the grounds on which an opinion is based, it is usually necessary that the facts should be stated hypothetically. It is impossible to lay down an absolute rule for all cases, and some discretion must undoubtedly be left to the justice presiding at the trial. In the present case, we think that the form of the question was such that it was properly excluded. It appears that the witness was afterwards permitted to testify upon the subject-matter of the offer of proof.

The purpose of the second question to the same witness, which was excluded, seems to have been to show that there would be a greater strain on the belt if it passed over a pulley 10 or 12 inches in diameter than if it passed over a pulley of larger diameter. If the witness was permitted to explain the nature and cause of the strain on a belt fastened together as this was, in passing over a pulley, it would be a natural inference that a small pulley would tend to bend the belt more than a large one; and, as the fastening was a stiff piece of iron, that this would tend to produce a greater strain on the belt at the point where the two ends were fastened together than would be produced by a larger pulley. There is no evidence that the pulleys used were not suitable and proper, and the witness, in his cross-examination explained the nature and cause of the strain on the belt, and, among other things, said: "The pulleys are entirely proper pulleys for such a belt. They are in ordinary use for such a belt. But it depends on the fastening. The pulleys were of the proper size to get that amount of speed. It makes a very hard strain on such a belt,--that is all,--and such a fastening." If the plaintiff should have been permitted to show the kind and amount of the strain resulting from the size of the pulley, as bearing upon the question whether the belt was properly fastened for the uses to which it was put, it seems to us that the subject was so far explained...