808 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



first organism in which the French savant succeeded in attenuating the 

 virulence and the first disease for which a vaccine made from atten- 

 uated organisms was prepared. Koch in 1878 described an organism 

 of similar pathogenicity as the bacterium of rabbit septicaemia and in 

 1886 the term hemorrhagic septicaemia was given by Hueppe to a num- 

 ber of infectious diseases of the lower animals in which hemorrhagic 

 spots were found in the tissues and internal organs. In 1900 Lignieres 

 discussed these bacteria, and named them as a genus, Pasteurellose, the 

 specific name given depending on the animal for which it was most 

 pathogenic. Thus he distinguished avian, porcine, ovine, bovine, 

 equine and canine Pasteur elloses. 



The specific characters of this group are small ovoid bacteria, often showing bi- 

 polar staining when treated with the aniline dyes, non-motile, no spores, Gram- 

 negative, polymorphic, not liquefying gelatin, no visible growth on naturally acid 

 potato, milk unchanged, no indol production, generally aerobic but also a facultative 

 anaerobe, virulence changeable, but usually very pronounced. 



The bacterium of fowl cholera, Bact. cholera gallinarum, or avian Pasteurellose, is 

 from o.5/x to 1.25^ long and 0.25^ to o.4o/x broad. It develops best at 37, and very 

 slowly at 20. It loses its virulence in cultures very quickly, and it succumbs 

 readily to desiccation. 



The disease is of frequent occurrence in Europe, but not often seen 

 in North America but some outbreaks have been reported in the United 

 States and Canada. Unfortunately it has been confused by poultry- 

 men with any disease characterized by excessive diarrhoea. The symp- 

 toms first noticed are the yellow color of droppings soiling the cloacal 

 feathers, then diarrhoea sets in, the character of the discharge varying, 

 being at times a fluid greenish mass, or a brown-red mucus, or a viscous 

 transparent and frothy fluid. The bird becomes uneasy, drinks copi- 

 ously and with a rise in temperature to 42 to 44 the bird becomes 

 drowsy and death follows. The period between the first noticeable 

 symptoms and death varies from one to three days. Chronic cases 

 sometimes occur and in these the bacterium is found with difficulty. 

 The birds become infected by way of the digestive tract, from eating 

 and picking up material infected by the discharges of diseased birds. 



Post-mortem indications are blackened combs, congestion of the 

 blood-vessels in the organs and intestines, and punctiform or large 

 hemorrhages of the duodenum, intestines and heart. The bacteria are 

 numerous in the blood, the pulp of all organs, and in the intestinal con- 

 tents. It is a true septicaemia. 



