§ 369. Certain cities; appointment of experts; compensation. The commissioner of health or health officer in cities having a population of less than one hundred seventy-five thousand, with the written consent of the mayor and subject to the approval of the board of estimate and apportionment or other board having similar powers in such cities and the common council or similar legislative authority in cities having no boards of estimate and apportionment or authorities with similar powers may temporarily employ such health and sanitary experts as may be necessary at a compensation fixed by the board of estimate and apportionment or other authority having power by charter to fix salaries of appointive officials.