Head of department; head teacher; class size limitation.

Whenever a department includes 2 or more high schools, then the teacher in charge of the department shall be designated “head of the department,” otherwise the teacher in charge of the department shall be designated “head teacher”; provided, that heads of departments as such have only an advisory capacity in educational matters and upon all questions shall be inferior in authority to the principal of each particular school; provided further, that no class shall be formed in the high schools with less than 10 pupils for a period not longer than 15 days.