The only question in this case is, whether the evidence of the chemist and of Dr. Means makes out such a case in favor of the fitness of this guano for the purposes intended, as to make the proof that it, in fact, did no good, immaterial. We may remark that the evidence of these two gentlemen does not make out with certainty that the precise article got by the defendant and his witnesses, is the very article they testify about. Sometimes, doubtless, a good article gets to be a bad *622one, by adulteration or exposure, before it comes into the bands of the consumer; but we do not agree that tbe evidence of a chemist, or of anybody else, that a certain article,, from tbe nature of its composition, is a good fertilizer, is proof conclusive of the fact. Theories do not always accord with experience. If an article professing to be a manure ordinarily fails as such when properly used, it is not a good manure, although the man of science may be very sure it is. It may be improperly mixed, etc. We recognize as true that a manure is not a bad one because it fails in a particular case, though even that is suspicious — it may be adulterated, but if it fails in the hands of many, properly using it in good seasons, it is asking a great deal to defendant for the opinion of a chemist, conclusiveness against the result of experience. The science of agriculture, and the law of the growth of plants, that mysterious process by which nature turns dead matter into living matter, is not so well understood even by scientific men as to make their opinions conclusive on such subjects.
Judgment affirmed.