The appropriate form of a medical certificate shall be filled in ink, or otherwise as may be specified by the Director General, by the Insurance Medical Officer in his own handwriting and shall contain a concise statement of the disease or disablement which in the opinion of the Insurance Medical Officer necessitates abstention from work on medical grounds or renders the person temporarily incapable of work. The statement of the disease or disablement in the medical certificate shall specify the nature thereof as precisely as the Insurance Medical Officers knowledge of the condition of the insured person at the time of the examination permits.