G. =The Bacillus Pyocyaneus.=--The bacillus pyocyaneus, a widely distributed organism, often observed in the skin and outside of the body; a motile, liquefying bacillus, growing at ordinary temperatures, seldom seen alone, but occasionally producing pus without association with other organisms; it stains the discharges and dressings a bluish-green and imparts sometimes an offensive odor. Suppuration caused by this bacillus is usually prolonged, but characterized by little constitutional disturbance. =Facultative Pyogenic Organisms=--_i. e._, those which have the power of provoking suppuration, but which have other and more distinct pathogenic activities as well. A. =Bacillus Typhi Abdominalis.=--This is found in many pus foci, developing during or after typhoid fever. It is occasionally met with alone, though most of these abscesses are really mixed infections. It is generally found in the bone or beneath the periosteum. Such abscesses are frequently seen in the ribs, and may not be noticed until months after convalescence from the fever. The pus contained within them is not always typical in appearance, but may be unduly thin or unduly thick. B. =Bacillus Proteus.=--Under this name are included three distinct forms, which were originally described by Hauser as distinct species, but which are now regarded as pleomorphic forms of the same organism. It is a motile bacillus, met with in decomposing animal and vegetable material, and occasionally found in the alimentary canal. It has been known to produce pus, especially in the peritoneal cavity and about the appendix. It may even cause general infection and peritonitis. C. =Bacillus Diphtheriæ.=--A non-motile bacillus, varying considerably in size and shape, changing the reaction in sweet bouillon from acid to alkaline; produces a dangerous infective inflammation of exposed surfaces, with tenacious exudate amounting to a distinct membrane. As a part of its life history it also produces a toxalbumin, which is one of the most powerful cell poisons known, the disintegration of the cell constituents due to its action being rapid and pronounced. This accounts for the heart failures which are often reported in connection with the disease. D. =Bacillus Tetani.=--More will be said about this organism when considering tetanus, and to that subject the reader is referred. The tetanus bacillus is occasionally found in pus which comes from the area through which the original infection was produced. But these bacilli do not travel to any distance in the human body, and are seldom found away from the area involved. Under most circumstances the pus is the product of a mixed infection. E. =Bacillus Œdematis Maligni.=--This organism will be more fully considered under a different heading. (See Malignant Edema.) It is a long, anaërobic bacillus, widely distributed in the soil and the feces of animals. It is believed that this, like the tetanus bacillus, may occasionally lead to formation of pus.