Section 55. Whoever acts as a collector of, dealer in or keeper of a shop for the purchase, sale or barter of junk, old metals or second hand articles without a license, or in any other place or manner than that designated in his license or after notice to him that his license has been revoked, or violates any such rule, regulation or restriction, shall forfeit twenty dollars. The purchase, sale or barter of books, prints, coins or postage stamps shall not be deemed to be the purchase, sale or barter of second hand articles within the meaning of this and the preceding section.