Right of licensee under section 84 to take proceedings against infringement.

    Any person to whom a licence has been granted under section 84 shall be entitled to call upon the patentee to take proceedings to prevent any infringement of the patent, and, if the patentee refuses or neglects to do so within two months after being so called upon, the licensee may institute proceedings for the infringement in his own name as though he were the patentee, making the patentee a defendant; but a patentee so added as defendant shall not be liable for any costs unless he enters an appearance and takes part in the proceedings.