Section 35. For the purposes of this section and sections 33 and 34, the term ''mortgage'' includes any deed of trust or other conveyance made for the purpose of securing performance of a debt or obligation, and no proceeding shall be considered begun until a memorandum, as required by section 15 of chapter 184, has been recorded in the registry of deeds for the county or recording district in which the real estate is situated. When any mortgage includes parcels in different ownerships at the time of recording of an extension, acknowledgment or affidavit the recording shall be sufficient only for the parcels which the owner or owners executing the extension or acknowledgment or named in the affidavit then appear of record to own. When the real estate is situated in more than 1 county or district, recording in any county or district shall be sufficient only for the real estate there situated. This section and sections 33 and 34 shall not revive, preserve or extend any mortgage otherwise ineffective nor affect enforcement of the debt or obligation otherwise than against the real estate mortgaged.