The doing of anything prohibited by this chapter shall be evidence of the violation of the provisions of this chapter relating to the thing so prohibited, and the omission to do anything directed to be done shall be evidence of a violation of the provisions of the chapter relative to the thing so directed to be done. The intent of any person doing or omitting to do any such act is immaterial in any prosecution for a violation of the provisions of this chapter. Any person who suffers, permits or allows any violation of the provisions of this chapter in any room or building occupied or controlled by him, shall be guilty of such violation and liable accordingly. Any person who shall keep, store or display any article or product, the manufacture or sale of which is prohibited or regulated by this chapter, with other merchandise or stock in his place of business, shall be deemed to have the same in his possession for sale. Every certificate, duly signed and acknowledged, of a chemist, analyst or other expert employed by the commissioner or any analysis, examination or investigation made by such analyst, chemist or expert with respect to any matter or product which the commissioner has authority to examine or cause to be examined, shall be presumptive evidence of the facts therein stated.