208 INFLAMMATION AND SUPPURATION 



bacillus of about the size of b. coli, straight or slightly curved, but 

 eoccoid and filamentous forms also occur, and a marked tendency to 

 involution forms is to be noted. It is actively motile, and possesses 

 numerous lateral flagella ; it does not form spores. It stains readily with 

 basic dyes and is Gram-negative. It grows readily on all the ordinary 

 media at room temperature, but best at the body temperature. In a 

 gelatin stab culture liquefaction appears within twenty-four hours ; it 

 spreads rapidly in the form of a funnel, and ultimately the whole medium 

 is liquefied and presents a turbid appearance. On gelatin plates the 

 characters are somewhat peculiar, especially when 5 per cent, gelatin is 

 used. The colonies are at first small spheres with granular' centre and 

 peripheral radiation extending into the medium ; liquefaction soon 

 follows, and from the superficial colonies offshoots extend over the 

 medium in tendril-like fashion, these being composed of bacilli in chains 

 placed side by side. Group's of bacilli may also become separate, move 

 over the surface of the medium, and form growths at a distance, — the 

 so-called "swarm-colonies." On an agar slope the organism forms a 

 moist layer, which extends over the whole surface of the medium ; in 

 this way, the bacillus can readily be separated from other organisms 

 present along with it. On potato it forms a slimy film with some 

 discoloration around it. It coagulates milk without acid reaction. The 

 organism is actively proteolytic and forms sulphuretted hydrogen, reduces 

 nitrates to nitrites, and ultimately to ammonia, and splits urea. It 

 forms acid and gas from glucose and mannite, but its action on other 

 sugars seems to vary. Although some cases of pure proteus infection 

 have been described, e.g., in pleurisy, the baeijli generally occur along 

 with other organisms in septic inflammations, such as cystitis and pyelitis, 

 endometritis, peritonitis, etc. Proteus organisms are also common in 

 gun-shot and other contaminated wounds. Cases of severe gastro- 

 enteritis apparently due to proteus have also been described (Horowitz). 



Bacillus pyocyaneus. — This organism occurs in the form of minute 

 rods 1'5 to 3 /i in length and less than '5 /j. in thickness (Fig. 49). 

 Occasionally two or three are found attached end to end. It is'actively 

 motile, possessing a terminal flagellum, and does not form spores. It 

 stains readily with the ordinary basic stains, but is decolorised by 

 Gram's method. 



Cultivation. — It grows readily on all the ordinary media at the room 

 temperature, the cultures being distinguished by the foimation of a 

 greenish pigment. In puncture cultures in peptone-gelatin a greyish 

 line appears in twenty-four hours, and at its upper part a small cup of 

 liqueiaction forms within forty-ei«ht hours. At this time a slightly 

 greenish tint is seen in the superficial part of the gelatin. The lique- 

 faction extends pretty rapidly, the fluid portion being turbid and showing 

 masses of growth at its lower part. The green colour becomes more and 

 more marked, and diffuses through the gelatin. Ultimately liquefaction 

 reaches the wall of the tube. In plate cultures the colonies appear as 

 minute whitish points, those on the surface being the larger. Under a 

 low power of the microscope they have a brownish-yellow colour and show 

 a nodulated surface, the superficial colonies being thinner and larger. 

 Liquefaction soon occurs, the colonies on the surface forming shallow cups 

 with small irregular masses of growth at the bottom, the deep colonies 

 small spheres of liquefaction. Around the colonies a greenish tint 

 appears. On agar the growth forms an abundant slimy greyish layer 

 1 which afterwards becomes greenish, and a bright green colour diffuses 



