delivered the opinion of the court.

In a trial for adulteration of milk an alleged expert from the chemical laboratory, as part of the government’s case in chief, was allowed to state, without objection as to his failure to be qualified, that the milk in question was adulterated. Then the defendant asked that the testimony be stricken out because the witness had not been qualified. While the court has a discretion to strike, the fiscal very properly said that the time to object was when the witness began to testify, implying of course that defendant waived the right probably because defendant knew witness was qualified or could qualify. The defence ma-de this remarkable statement: “Then the defence would not have availed me.”

In other words, the idea of the defendant was that he-could suffer testimony to be given and then hope that he could technically exclude it by moving its elimination. Not only was the fiscal right in saying that the objection was late, but the court has an ample discretion to reopen- the case or to permit the witness to qualify nunc pro tunc, so to speak. In the present case the court agreed with the fiscal, but, to obviate any difficulty, permitted the examination to be made to test the expert capacity of the witness. The defendant objected that the fiscal had finished his direct examination and that the period of cross-examination had arrived. The court overruled the objection. The order of proof is always within the sound discretion of the trial court. These considerations dispose of the first assignment of error.

It would seem that the practice is for the inspectors to-add some preservative or formol to the milk seized. Such a measure was taken in this case. The defence offered testimony to show that the added preservative caused the apparent adulteration. Thereupon the government offered an expert to testify as to the effect of this preservative or formol. The second assignment of error is as follows r ‘ ‘ The court committed error in allowing witness Eafael Pérez: *17Porrata to testify and rebnt in a general way the testimony of Angel M. Pesquera, an expert for the defence.” The basis of this assignment, to judge from the citation appellant makes, is that the condition of the milk is a primary issue in the case and cannot be proved by the the mere opinion of experts. The defence, however, introduced expert testimony to show that the addition of formol did or could adulterate the milk. His expert could not possibly know that the addition of the preservative had actually adulterated the milk. It was essentially the mere opinion of defendant’s expert that such addition could adulterate. To this scientific supposition the government had a complete right to counter,, and did. Likewise, we have examined the evidence andi while some of the questions put to the expert were not in best form, he gave clear testimony tending to show that the addition of formol did not cause the adulteration or the increased amount of water.

The third and fourth errors relate to the weighing of the proof by the court in this battle of experts. This was a matter of the weight of the evidence and we find no error in the finding of the court.

The judgment should be

Affirmed.