This is one of the commonest bacteria. It appears as blood-red stains on objects - sometimes on milk, bread, starch, etc., from which the names "blood-rain," "bleeding host," were derived. As the blood-red spots have sometimes been regarded as portents or prodigies, the bacteria have received the specific designation Prodigiosus. The individuals are oval in shape, or very short rods, and they grow vigorously on the surface of potatoes, or on nutrient jellies, and give a deep red colour. The colour is not resident in the bacteria but secreted by them. The bacteria evidently exist abundantly in the air and readily infect any suitable medium which may be exposed. They absorb readily the aniline dyes. No pathological significance is attachable to this form.