The business of cemeteries shall not include among its corporate powers, either by express grant or as an incident thereto, the right to engage in any business enterprise or occupation such as is usually pursued by private individuals. Nevertheless, this provision shall not exclude the right of cemeteries to sell corner posts and other implements to define the boundaries of lots or other subdivisions of such cemeteries, and articles incident to the care and maintenance of lots and burial spaces, and the right of cemeteries to furnish or sell materials necessary for a complete cemetery burial service.