Section 55. Whoever exposes for sale oleomargarine which is not marked and distinguished by all the marks, words and stamps required by section forty-nine, or whoever does not have upon the exposed contents of each opened tub, package or parcel of oleomargarine a conspicuous placard with the word ”oleomargarine” or ”margarine” printed thereon in plain, uncondensed gothic letters, not less than one inch long, or whoever himself or by his agent sells or offers for sale any oleomargarine to any person who asks or sends for butter, shall be punished by a fine of one hundred dollars.