CHAPTER XXI 



BACTERIACE.E: THE BACTERIA OF THE HEMOR- 

 RHAGIC SEPTICEMIAS, PLAGUE AND 

 MALTA FEVER 



For the bacteria of the hemorrhagic septicaemias the Com- 

 mittee of the Society of American Bacteriologists has adopted the 

 generic name, Pasieurella Trevisan 1887. 



Bacillus Avisepticus (Pasteurella Cholerae-gallinarum). 

 Moritz^ in 1869 observed this minute rod in the blood of chickens 

 with chicken cholera. Toussaint (1879) and Pasteur (1880) obtain- 

 ed pure cultures in liquid media and Pasteur (1880) made the far- 

 reaching discovery of the method of immunization by means of at- 

 tenuated bacterial cultures while working with this organism. B. 

 avisepticus occurs in enormous numbers in the blood , internal organ s, 

 urine and feces of the acutely affected birds, iniar smaller numbers 

 in those having the chronic form of the disease and has also been 

 found in the intestinal contents of apparently healthy birds . It 

 is o.3;u wide and 0.2 to iju in length, the shorter ones being joined 

 together. It is non-motile and Gram-negative. Cultures are 

 readily obtj|,ined on ordinary media by inoculation with heart's 

 blood. Gelatin is not liquefied. Minute quantities of a virulent 

 culture suffice to produce a fatal infection in chickens and many 

 other birds, either by feeding or by subcutaneous injection. 

 Rabbits are also extremely susceptible, guinea-pigs almost immune. 

 Artificial cultures kept for three to ten months in contact wi^'h air 

 are no longer capable of causing a fatal infection in chickens and 

 their injection is followed by recovery and a state of immunity to 

 the fully virulent organism. Acute chicken cholera is the typical 

 hemorrhagic septicemia of birds, with abundant bacteria in the 

 blood, and hemorrhages on the seroiis membranes and into the 

 stomach and intestine. 



'■ Vallery-Radot : Life of Pasteur, 1911, Vol. II,ip. 75- 



329 



