Section 43B. The sale of cemetery lots and plots, or the sale of crypts in a community mausoleum or niches in a columbarium, for speculative purposes, or the conveyance of any portion of a cemetery already dedicated to burial purposes as security for debt, is hereby prohibited, and every such conveyance shall be void and of no effect. Whoever makes or attempts to make a sale or conveyance contrary to the provisions of this section shall be subject to the penalty provided by section forty-three N.