Certain kinds of bacilli, when conditions became unfavorable for life, were capable of creating, from themselves, bodies called spores. What they did was condense their cell contents into an oval body with a thick wall. This body, when completed, detached itself from the bacillus and became a free spore, highly resistant to physical and chemical change. Later, when conditions were more favorable for survival, the spore germinated again, bringing into existence all the qualities of the original bacillus.
