MORPHOLOGY 277 



Rabbits. Sub-cutaneous inoculation in rabbits is rarely fatal : intra- 

 peritoneal inoculation does not give constant results. 



The injection of 1 c.c. of a broth culture into the ear vein of a rabbit, which 

 is the most certain method of producing infection, causes an acute disease. 

 The animal suffers from fever, albuminuria and diarrhoea and dies in 24-48 

 hours. The organisms are very numerous in the liver, spleen and kidneys but 

 only a few are to be found in the blood. 



Inoculation of smaller doses of culture leads to a chronic but not necessarily 

 fatal disease in the rabbit which is characterized by wasting, paralysis 

 of the limbs and convulsions. If death take place it is not uncommon to 

 find post mortem a true nephritis with small contracted kidney, and even 

 hypertrophy of the left ventricle of the heart. In some cases there is amyloid 

 degeneration of the kidneys and infarcts may be present in the alimentary 

 mucosa (Charrin). 



By feeding rabbits with the organism Brau produced fatty degenera- 

 tion of the liver and ulceration of the intestine followed by generalization of 

 the bacillus in the tissues of the animal. 



Guinea-pigs. In guinea-pigs, sub-cutaneous inoculation produces a local 

 swelling followed by ulceration : the organism then becomes disseminated 

 and the animal dies. Intra-peritoneal inoculation is more severe and death 

 takes place rapidly ; the bacillus is found in the blood. 



Rats. Mice. The results are the same as in the guinea-pig : mice are 

 very susceptible. 



An organism isolated by Besson from the water of Zaghouan killed white 

 rats in 20-36 hours when inoculated sub-cutaneously in doses of O20 c.c. 

 Post mortem the abdominal organs *were congested, the peritoneum contained 

 a small quantity of an almost clear fluid and the intestines showed an early 

 stage of ulceration in many of the Peyer's patches : in two cases the animals 

 had heematuria and the organism was found in the blood, liver, kidneys, 

 peritoneal fluid, intestinal contents, and in the urine in the bladder. 



Increase of virulence. The virulence of the bacillus pyocyaneus can be 

 increased by passage through rabbits to such an extent that after a few 

 passages a dose of 0*1 c.c. of a broth culture 

 rapidly kills animals of this species. V 



SECTION II. MORPHOLOGY. ^ ^ v ^J ^ 



1. Microscopical appearance. ,M /,Jn /' * 



The bacillus pyocyaneus is a small motile rod- vV ^ % 



shaped [non-spore bearing] organism with rounded // f ' 

 ends, and of variable size. Its average length is "** x 



about 1-5/A and its breadth O5 to 0'6/x. It has / * * 



one flagellum situated terminally [monotrichous]. ^ v ^ ft % 



Staining reactions. The bacillus pyocyaneus is Fm 17 ^_ Bacmus pyocyaneus . 

 easily stained by the basic aniline dyes and is Film from an agar culture (dilute 

 gram-positive. ^S^^' (OcJii ' obj " l = th ' 



The bacillus stains rather badly by Gram's method : 



some strains stain feebly and irregularly, and decolourization takes place easily if 

 the action of the alcohol be prolonged. 



Morphological variations. The morphology of the bacillus pyocyaneus 

 undergoes considerable change if sown in media containing small amounts 

 of antiseptics (Guignard and Charrin). For instance, in broth containing 

 O02 per cent, of carbolic acid the organism is long and filamentous. The 

 addition of alcohol and bichromate of potassium to the medium have a 



