Any sergeant at arms or court crier who shall have served as such for a continuous period of twenty years, whether he has reached the age of sixty years or not, who shall be found as hereinafter provided to be physically unfit for further service shall, upon application in writing to the judge of the court to which said sergeant at arms or court crier shall be attached at the time, be retired upon half pay.
N.J.S. § 43:10-76