That in case of a vacancy happening by death, resignation or otherwise, in any office created by the constitution or laws of this commonwealth, and where provision is not already made by said constitution and laws to fill said vacancy, it shall be the duty of the governor to appoint a suitable person to fill such office, who shall be confirmed by the senate, if in session, and who shall continue therein and discharge the duties thereof till the first Monday of January next succeeding the first general election which shall occur three or more months after the happening of such vacancy.