Every person who holds a mortgage of any proprietary right in any estate may apply to the Collector for registration of his name as such mortgagee, and of the interest in respect of which he is such mortgagee, and in such application shall specify whether he or the mortgagor is in possession. On receipt of such application the Collector shall proceed, as far as possible, according to the manner hereinafter prescribed in respect of applications for registration as proprietor.
