Microbiology is an important field of biology and medicine and deals with microorganisms (bacteria, fungi, protozoa or viruses) and their habitats and conditions. For this it is essential to cultivate bacterial strains or microorganisms and to observe their growth. The square bottle according to Breed-Demeter is suitable for the determination of spore-forming bacteria in milk (germ count or bacteria counting method). Due to the shape of the bottle, the germs can be observed directly in the bottle using a microscope (no germ extraction necessary).