¶1The question, “Don’t you think it was lager beer ? ” was properly allowed to be put. The application of a class name to an object perceived by the senses is generally the expression of an inference, and testimony would be impossible if such inferences could not be stated. If the witness had said that it was lager beer, his testimony would only have meant that he confidently thought or inferred from the qualities directly perceived by him that the substance had the other qualities denoted by the name. As he would have been allowed to testify to such a confident inference, he could be asked, on cross-examination, if he did not draw that inference, although with less than absolute certainty. Even if the question had been inadmissible, the answer made it harmless, as the witness replied that he could not say.
¶2The witness having testified that the beer was a weak beer, it was open to the prosecution to show that he had previously testified that he thought it was lager beer, for the purpose of contradicting his present testimony, if for no other purpose. Pub. Sts. e. 169, § 22. Day v. Cooley, 118 Mass. 524. Brooks v. Weeks, 121 Mass. 433. The exceptions do not disclose any *465attempt to use this testimony as substantive evidence that the beer was lager beer, and there is no question of the sufficiency of the whole evidence raised; nor does it appear that all the evidence is before us.
¶3Exceptions overruled.