The county board of education, subject to the rules and regulations of the State Board of Education, shall cause to be taken, under the direction of the county superintendent of education, a quadrennial school census of the children in the county between the ages of six and 19, inclusive. The school census shall be taken in July of 1946, and thereafter every four years, and the county superintendent of education, upon the direction at any time of the State Superintendent of Education, shall cause the whole or any part of any school census in his county to be retaken.