When the environment becomes unfavorable, these cells undergo the process of sporogenesis, and form intracellular endospores. When the vegetative cell degenerates and dies, the endospore is released as a spore. When conditions become favorable, the spore germinates to become a vegetative cell again. Do not confuse bacterial spores with fungal spores, which are very different structures. Special staining procedures must be used to visualize spores with the compound microscope.
Malachite green is the primary stain.
In addition, the stain must be heated to penetrate the spore coat. The bacteria are decolorized with water. Malachite green is soluble in water unless it is bound to the spore coats. Safranin is the counterstain. Descriptions of endospore locations within bacterial cells.