¶1The appellants, proprietors of a cheese factory, had a contract with respondent for the delivery of milk. This contract contained a stipulation that if the respondent delivered milk which was adulterated, skimmed, or watered he should he liable to a penalty of $50 to be paid to the appellants, and by appropriate provisions appellants’ damages were fixed at that sum in case of such breach. In this action to recover these damages the appellants made proof of the delivery of milk by the respondent from which samples were taken and submitted to what is known as the Babcock test. The specific gravity and the angle of refraction thereof were ascertained and compared with other samples of milk from the same herd, and from these tests the chemists concluded that there was seventeen per cent, of water in the milk- in question. Tide respondent had also pleaded guilty in a criminal prosecution for the same act. This would not conclude him in the instant case from denying that-he watered the milk. The respondent and his wife and son, who attended to the milking and delivery of the milk on the day in question, testified that no water was added to the milk. The jury found a verdict for defendant, and it is argued that the verdict should have been set aside as unsupported by evidence.
¶2Although there might in our opinion be a preponderance of evidence against the respondent we cannot disturb the verdict for such reason. Under the common-law system the jurymen are triers of questions of fact. That practical system, founded upon ages of experience, recognizes that even granting substantial accuracy to chemical analyses and scientific tests when carefully made under proper conditions, yet these analyses and tests are made by fallible human hands, directed by fallible human minds, and subject to errors and inadvertences, and the narrative thereof also must always rest at last upon the veracity of the operator or operators. Hence there was a question for the jury to decide.
¶3It is contended that defendant’s wife was not a competent *80witness in Ms behalf; but she milked some of the cows and handled some of the milk on the morning in question for her husband, who was the owner thereof and who delivered the milk. For tMs reason she was a competent witness. Rhyner v. Carver, 84 Wis. 181, 53 N. W. 849; Northwestern Nat. Ins. Co. v. Roberts, 90 Wis. 210, 62 N. W. 1048. It was necessary for respondent to call his wife as a witness, otherwise his defense would be left subject to the imputation that she was the one who put the water in the milk which he delivered to appellants.
¶4We do not think there was error in permitting the witness Klassy, a dairy farmer owning eighty to one hundred milk cows, to give his opinion respecting the effect of fodder upon the quality of milk. Whitney v. C. & N. W. R. Co. 21 Wis. 321; Hamann v. Milwaukee B. Co. 127 Wis. 550, 106 N. W. 1081.
¶5Finding no error in the record the judgment should he affirmed.
¶6By the Court. — Judgment affirmed.