530 



DESCRIPTION OF SPECIES. 



On potato a dry rust-brown 

 growth appears at the seat of 

 inoculation, which becomes green 

 when treated with ammonia. 



The pigment formed by the micro- 

 organism is a definite principle 

 pyocyanin. It can be extracted 

 with chloroform from pus and from 

 washing of bandages ; it is soluble 

 in acidulated water, which it colours 

 red. In neutral solution it becomes 

 blue. It crystallises in chloroform 

 in long needles ; and forms some- 

 times lamellae and prisms. 



They cause death in guinea-pigs 

 whh injected into the abdominal 

 cavity. Eabbits are not killed by 

 intravenous injection. 



The bacilli are antagonistic to 

 anthrax bacilli. Charrin and others 

 have shown that rabbits inoculated 

 with a pure- culture of Bacillus 

 pyocyanus after inoculation with 

 Bacillus an thracis will not succumb 

 to anthrax. Woodhead and Wood 

 produced similar results by using 

 sterilised cultures, showing that the 

 results were due to the chemical 

 products of the bacilli. 



The rods occur in the pus of those 

 cases in which the wounds and pus- 

 stained bandages exhibit a greenish- 

 blue colour. 



Bacillus pyogenes feet id us 

 (Passet). Small rods, about 1'45 /u, 

 in length, and -58 p. in width ; 



FIG. 209. BACILLUS PYOGENES 

 FCETIDUS, x 790 (PASSET). 



often in pairs, or linked together 

 in chains. They are motile, and 

 spore-formation occurs. 



Colonies like white points appear 

 after twenty-four hours, and de- 

 velop into greyish spots, and these 

 enlarging coalesce into a layer. 



Cultivated in nutrient gelatine 



a greyish, veil -like growth forms 

 on the surface. 



In nutrient agar-agar the culti- 

 vation resembles the growth in 

 gelatine. On blood serum a moder- 

 ately thick greyish-white streak 

 develops, and on sterilised potato 

 an abundant, shining, brownish 

 culture. 



From all these media a putrid 

 odour emanates, but no smell is 

 detected from a cultivation in milk. 



Inoculated into mice and guinea- 

 pigs, abscesses are produced or death 

 from septicaemia results. 



They were isolated from putrid 

 pus. 



Bacillus pyogenes soli(Bolton). 

 Rods resembling Bacillus diph- 

 theriae. 



Colonies granular, faintly yellow. 



The bacilli inoculated in the depth 

 of gelatine form colonies in the 

 track of the needle. 



They are pyogenic in mice and 

 rabbits. 



They are present in earth. 



Bacillus radiatus (Luderitz). 

 Rods 4 to 7 /i in length, *8 p in 

 width, and filaments. Motile. 

 They are anaerobic. Spore-forma- 

 tion present. 



Colonies are composed of delicate 

 interlacing filaments. 



In the depth of gelatine a growth 

 occurs at the lower part of the 

 needle track, from which fine fila- 

 ments are given off in the sur- 

 rounding gelatine, and liquefaction 

 follows. The growth in the depth 

 of agar is also composed of fine 

 filaments. 



In sub-cultures they produce a 

 cloudy liquefaction. 



Cultures have a peculiar odour. 



They occur in earth. 



Bacillus radiatus aquatilis 

 (Zimmermann). Rods 1 to 6'5 /* 

 in length, -65 // in width. 



Colonies white, with a marginal 

 zone of radiating filaments. 



The bacilli inoculated in the 

 depth of gelatine grow in the track 

 of the needle, and excavate and 

 liquefy the surrounding gelatine, 

 and form on the free surface a 

 wrinkled patch, which later subsides 



