The competency of an alleged expert witness is a preliminary question of fact to be determined by the trial court, and its determination that the witness is competent will be generally regarded as conclusive, unless there is no evidence whatever, or no sufficient evidence, to support it, or the determination is contrary to the evidence. So says the General Term of the Court of Common Pleas of New York City and County, in its decision of the case of Haas v. Green, rendered Feb. 5, 1894. That an expert witness has changed his employment, for example, has abandoned his studies as a chemist and devoted himself to the occupation of a druggist, vending drugs and toilet articles exclusively, this court further holds, does not render him any the less competent.