239. Provisions to be inserted in equitable mortgage in writing.

The written agreement to execute a mortgage must incorporate all terms which the parties have expressly agreed1, but need not incorporate those implied by law2. An agreement to execute a legal mortgage, with such powers and provisions and in such form as the mortgagee may require for further securing the principal money and interest, only extends to reasonable provisions, and does not enable the mortgagee to insert terms excluding the operation of the statutory provision