In filing papers in the judge of probate‘s office the case shall be divided into convenient apartments, which shall be numbered from one forward. The papers relating to the same estate shall be wrapped in an envelope as a package, shall bear a number and shall be endorsed in the name of the estate. A convenient number of packages shall be embraced in a strong envelope and constitute a bundle, bearing the number of the apartment of the case containing it. A complete alphabetical index shall be constructed with reference to the surname of the deceased person to whose estate the papers relate and of the executors and administrators. Opposite each name in such index shall be two columns, the one expressing the number of the apartment where the bundle is to be found and the other expressing the number of the package in such bundle which contains the papers relating to the estate named in the index.