in t 



ISOLATION OF THE ORGANISM 281 



in this manner with doses of O'5-l c.c. of a broth culture on five or six occa- 

 sions at intervals of 3 or 4 days : or by inoculating them with small doses 

 of filtered cultures or cultures heated at 115 C. 



The blood and urine of animals treated with filtered cultures will also 

 immunize animals. 



Wassermann immunized guinea-pigs by inoculating them in the peritoneal 

 cavity with gradually increasing doses of living culture or toxin. Guinea- 

 pigs vaccinated with living cultures show a permanent immunity to the 

 organism, but an inoculation of toxin is fatal to them. Their serum is pro- 

 phylactic and has feeble therapeutic properties, but is not antitoxic. Guinea- 

 pigs vaccinated with toxin are immune against both the organism and 

 the toxin, and their serum is prophylactic, distinctly therapeutic and 

 antitoxic. 



The bacillus pyocyaneus will grow in the serum obtained from immunized animals : 

 it preserves its shape, its vitality and its virulence, but forms agglutinated colonies 

 (Charrin and Roger, Gheorghiewsky) and produces no pigment. The serum of 

 immunized animals is therefore not bactericidal ; it is simply agglutinating in vitro. 

 The agglutinating property does not run parallel with the prophylactic property. 



4. Agglutination. 



The agglutinating property of the blood of vaccinated animals has just 

 been referred to. The blood of infected persons when diluted 1 in 40 to 1 in 

 100 similarly agglutinates the bacillus, and normal human serum has in some 

 cases an agglutinating action in a dilution of 1 in 10. To demonstrate the 

 agglutination it is best to add the serum to an emulsion prepared by diluting 

 in normal saline solution the centrifuged deposit of broth cultures at least 

 24 hours old. 



5. Antagonism. 



The Bacillus pyocyaneus impedes the growth of anthrax in cultures. In 

 the same way by inoculating a mixture of the anthrax bacillus and the 

 bacillus pyocyaneus into animals susceptible to anthrax the animals do not 

 become infected with anthrax. Porcelain-filtered cultures of the bacillus 

 pyocyaneus possess the same properties (Blagovetschensky). 



Similarly the bacillus pyocyaneus will prevent the development of the 

 cholera vibrio (Kitasato). 



Rumpf has recorded a parallel antagonism between the bacillus pyocyaneus and 

 the typhoid bacillus ; he successfully treated 65 cases of enteric fever by inoculating 

 the patients with sterilized cultures of the bacillus pyocyaneus. It does not appear 

 that much faith should be put in these statements. Analogous investigations 

 undertaken on the guinea-pig by Besson led him to the conclusion that these animals 

 when treated with filtered cultures of the bacillus pyocyaneus are more than normally 

 susceptible to the action of the typhoid and colon bacilli : moreover, infection 

 with the bacillus pyocyaneus has been recorded coincidently with a fatal attack 

 of enteric fever in man. 



SECTION IV. DETECTION, ISOLATION AND IDENTIFICATION OF 

 THE BACILLUS PYOCYANEUS. 



The presence of the bacillus pyocyaneus in pus is detected by the blue 

 colour of the dressings and by the characteristic smell of the wound. 



Pus should be examined by staining films with gentian-violet or thionin. 

 The bacilli can be easily isolated on gelatin plates on which they produce a 

 characteristic appearance. At the post mortem examination cultures should 



