Whenever it shall appear from any proper showing, or from any examination made, that the assets and resources of any domestic mutual insurance company are insufficient to meet the minimum conditions prescribed in section 44-219 as now existing or hereafter amended, the Department of Insurance shall promptly determine the amount of such deficiency, and thereupon issue a written notice and requisition to the directors and officers of such company, requiring them to make good the amount of such deficiency within a reasonable time, not to exceed one hundred eighty days, from the service of such notice and requisition.