But public secular schools and public denominational schools, properly so-called, also may continue, and their existence is constitutionally guaranteed. These schools, by the same title as the mixed schools, are elementary schools, on which may be based secondary and higher education. But these cannot be established in municipalities except under certain specified conditions. There must first be a formal demand on the part of a sufficient number of heads of families. Then the organization of the school asked for must conform to high educational standards. From all this it may be concluded that the system of the uniform school and the transition from the public school to secondary and higher schools must not be interfered with. In addition, the arrangement of instruction based on the diverse vocational needs, must not be made impossible. Finally, public instruction must not be handicapped by the unnecessary establishment of useless and inefficient schools. The wishes of heads of families, as far as possible and in accordance with the above conditions, must be taken into consideration and their proposals accepted. Questions of detail, such as, what is understood by “head of a family”; how many such are sufficient within a municipality to be able to demand a sectarian or a secular school; how many schools there shall be and of what kind, must be settled by educational laws of the Reich and by laws of the States which must follow those of the Reich. * * * * * II.--_Private instruction is permitted._ (Article 142.) However, this liberty is subject to important restrictions (Article 147) in the case of private schools considered as substitutes for public schools. In general, establishments of private instruction, no matter of what grade, can be created only _by the authorization of the State_. This authorization is subject to the following conditions: the programme and the equipment of private schools must not fall below the programme and equipment of public schools. The scientific training of teachers of private schools must be of as high a standard as that of public school teachers. The economic and legal position of private school teachers must be guaranteed. Finally, private schools cannot become the schools of class or caste. Elementary private schools are subjected by the Constitution to several special conditions. Their establishment is authorized when in any municipality there does not exist for a minority of heads of families, whose needs must be considered, a public school of their denomination, or one that conforms to their ethical system. Such a school may also be established if educational authorities recognize in the demands of such a group a special pedagogical interest. The Constitutional provisions relating to programmes and free instruction apply also to private elementary schools. Private preparatory schools are abolished.