The aim of this study is to supplement the general complex of problems concerned with forms of instruction using concrete examples drawn from the teaching of chemistry. It defines the external as well as internal conditions of organising the process of teaching and learning. The former include e. g. the compulsory or optional character of instruction, the number of pupils and their division into groups, the place of instruction; the latter (which are shown in concrete examples of various possibilities of organising experiments in chemistry) include e. g. the person carrying out the experiments, the tempo of work and the like. As regards the external form of teaching chemistry, the following are mentioned: lesson of the basic type, laboratory exercises, excursion, chemistry practice, hobby group, after-school classes for slow learners, chemical party, chemistry Olympics, individual forms of instruction; simultaneously „also possibilities of the internal organisation of the process of teaching and learning are discussed in concrete situations with regard to the use of chemical experiments (e. g. instruction with the demonstrational experiment, with frontal experiments of pupils etc.). However, the teacher’s work as well as the pupils’ work can be organised in various ways not only in chemical experiments but also in using other pedagogical media, and therefore internal organisation of instruction in a broader sense is spoken of (examples are given which simultaneously prove the close relationship between the forms of instruction and teaching methods, whether they are verbal, visual or practical). All the possibilities of external and internal forms of teaching chemistry together with an indication of their relation to teaching methods are summarised in a table under the heading ≫The system of forms of instruction in chemistry≪.