SUPPURATION. 197 coccus-infection, both general and local. Numerous cases are upon record in which the serum seemed to exert a beneficial action. It would seem as if an antiphlogistic serum should occupy an important place in the future of medicine. The serum is prepared upon the same plan as that of Behring, except that living virulent streptococci instead of the sterile toxin are injected into the horse. BACILLUS PYOCYANEUS. In some cases the pus evacuated from wounds exhibits a peculiar bluish or greenish color, from the presence of FIG. 56.—Bacillus pyocyaneus, from an agar-agar culture; x 1000 (Itzerott and Niemann). the Bacillus pyocyaneus (Figs. 56, 57). This is a short, delicate bacillus of small size, measuring 0.3 : 1-2 fa ac- cording to Flugge, frequently united in chains of four or six. It has round ends, is actively motile, has one terminal flagellum, does not form spores, and can exist with or without oxygen, though it is an almost purely aerobic organism. It stains well with the ordinary solutions, but does not retain the color by Gram's method.