A member of the county police department who shall have received permanent disability in the performance of his duty shall, upon the certificate of a surgeon, the county physician or another physician designated for that purpose by the pension commission, be retired on a pension equal to two-thirds of the amount of his salary at the time of his retirement.

When a member or employee of the department desires to retire because of injury or disease, he shall apply in writing to the pension commission for retirement. Thereupon, the commission shall call to its aid the county physician or other physician designated for that purpose, and the applicant may also call to his aid a regularly licensed and practicing physician or surgeon. The president of the board of pension commissioners may administer oaths to such physicians or any person called regarding the matter before the commission. If the two physicians so called fail to agree on the physical condition of the applicant, the commission may call a third disinterested practicing physician and surgeon. The determination of a majority of these three physicians, after they have first been duly sworn in the case, shall be reduced to writing and signed by them. The pension commission shall determine by resolution whether the applicant is entitled to the benefits of this article and shall consider the physicians’ determination in arriving at its decision.