Section 59. Whoever himself or by his agent sells, exposes for sale or has in his custody or possession with intent to sell, an article or compound commonly known as process butter, and produced by taking original packing stock or other butter, or both, melting the same, so that the butter fat can be drawn off, mixing the fat with skimmed milk, or milk, cream or other milk product, and rechurning the mixture, or by any similar process, shall have ''renovated butter'' conspicuously stamped, labelled or marked so that the words cannot easily be defaced, in a straight line in printed letters not less than one half inch in length, of plain, uncondensed gothic type, upon the top, side and bottom of each tub, firkin, box or package containing said article or compound. The seller at retail of said article or compound which is not in the original package shall himself or by his agent attach to each package so sold and deliver therewith to the purchaser a label or wrapper bearing conspicuously upon the outside thereof the words ''renovated butter'' in printed letters not less than one half inch in length, in a straight line of plain, uncondensed gothic type. Whoever violates any provision of this section shall for the first offence be punished by a fine of not less than twenty-five nor more than one hundred dollars, for the second offence by a fine of not less than one hundred nor more than three hundred dollars, and for a subsequent offence by a fine of five hundred dollars or by imprisonment for not less than two nor more than three months.