The question to be decided is whether when a city, which has adopted one plan of charter under G. L. c. 43, changes to another plan under the same chapter, all members of the school committee go out of office and an entirely new board must be elected. The passage of St. 1915, c. 267, of which G. L. c. 43 is the present form, was an innovation in city charter legislation. It could be made applicable under the Constitution only to municipalities already established and existing as cities under art. 2 of the Amendments to the Constitution. It provided four different forms as models of city charter. These are described in G. L. c. 43, § 1, in these words:
“‘Plan A,’ a city government and legislative body composed of the mayor and the city council, the councillors being elected at large.
“ ‘Plan B/ a city government and legislative body composed of a mayor and city council, the councillors being elected partly at large and partly from districts or wards of the city.
“ ‘Plan C/ a city government and legislative body composed of a mayor and commissioners as hereinafter specified.
“‘Plan D,’ a city government and legislative body composed of a mayor and four councillors, and an administrative officer, called the city manager, whose powers and duties are defined in sections eighty-nine to ninety-two, inclusive.”
Certain general provisions are common to all the forms. It is enacted by § 45 of G. L. c. 43 that sections one to forty-four, both inclusive, shall upon the adoption of any of the plans apply to such plan except as is otherwise provided in such plan. The arrangement of the chapter is graphic. The first forty-five sections are under the topical heading “ General Provisions.” Then follow these headings:
“Plan A. — Government by mayor and city council elected at large,” which includes sections forty-six to fifty-five, inclusive.
“Plan B.— Government by mayor and council elected by districts and at large,” which includes sections fifty-six to sixty-three, inclusive.
*290“Plan C. — Commission form of government,” which includes sections sixty-four to seventy-eight, inclusive.
“Plan D. — Mayor, city council and city manager,” which includes sections seventy-nine to ninety-two, inclusive.
This vivid and pointed arrangement of the parts of the chapter has an indication that when a change from one plan to another is made by any city, the general provisions continue in force unaffected by the adoption of a different one of the four special models from the one hitherto accepted. This indication is accentuated by the provision repeated in each plan to the effect that upon its adoption the plan “shall become operative as provided in sections one to forty-five, inclusive.” Thus each separate plan is explicitly linked to the general provisions. The distinguishing features of the four several plans relate to the mayor and council or commissioners or city manager and not to the school committee.
An examination of the chapter in detail shows that it does not require a clean sweep of all city officers when one plan is adopted in place of another. In § 11 are the words that the “officers provided for under the plan so adopted shall be elected . . . and their terms of office shall begin at ten o’clock in the forenoon of thejfirst Monday of January following their election.” These words mean that when for the first time a city resorts to that chapter for its charter and adopts one of these plans, all city officers required by the chapter must be elected; and that when change is made from one plan of the chapter to another plan of the chapter, only those officers required by the newly adopted plan so far as different from those required under the discarded plan shall be elected. There is nothing in § 15 at variance with this view.
The general provisions, §§ 1 to 45, contain all that is said in c. 43 concerning the school committee. The election of the school committee is set forth in § 31. It there is said: “At the first annual city election held in any city after its adoption of one of the plans provided in this chapter . . .” This applies, we think, to the first annual city election after a city comes under the operation of the chapter by adopting any one of the plans. It does not mean that, when in a city already subject to the chapter *291a change from one plan to another is made, there must be a new election of the school committee.
Every practical consideration supports this conclusion. The school committee under all the plans consists of the same number elected in the same way. Continuity of sound policy is highly desirable in the administration of schools. The history of legislation concerning the election of the school committee shows persistent effort to remove that board from partisan politics. Leonard v. School Committee of Springfield, 241 Mass. 325. Powers are conferred upon the school committee by §§33 and 34 of c. 43 in addition of those of G. L. c. 71, relating to the general powers of school committees. Every reason exists for a continuous board executing a policy changeable by the slower processes available by the opportunity of electing one third only of the members each year.
There is nothing in Cunningham v. Mayor of Cambridge, 222 Mass. 574, and Mayor of Cambridge v. Cambridge, 228 Mass. 249, in conflict with this conclusion. Those decisions and the words there used were directed to the first vote of a city coming under the provisions of G. L. c. 43 and its predecessor. See Swan v. Justices of the Superior Court, 222 Mass. 542, 545.
The city of Waltham adopted Plan D in 1917 and changed to Plan B in 1922. It follows that all members of the school committee do not go out of office, but only the two whose terms expire in January, 1923.
The result is that a writ may issue directing the respondents to make the preparations required by law for the election of two members only of the school committee at the city election to be held on December 19, 1922. Police Commissioner of Boston v. Boston, 239 Mass. 401, 409.
So ordered.