CHICKEN CHOLEKA 405 



freely on the various culture media from 20 to 38 C., on agar 

 forming a thick, moist, cream-coloured layer, on gelatin a shining, 

 white, expansive growth without liquefaction. In broth a general 

 turbidity forms, but growth on potato is indifferent. It produces 

 acid, does not ferment glucose or lactose, is aerobic and faculta- 

 tively anaerobic, does not form spores, and is killed by a tempera- 

 ture of 60 C. in fifteen minutes. If dried it dies in a few days, but 

 retains its vitality for a considerable time in damp earth or in water, 

 and so infection is readily conveyed. Fowls die after subcutaneous 

 intramuscular or intravenous inoculation and by feeding, the 

 organisms being found abundantly in the blood. Post-mortem, the 

 serous membranes may be inflamed and haemorrhagic, the liver 

 large and soft, and the intestine shows haemorrhagic spots, and is 

 sometimes ulcerated and contains a mucoid fluid stained with blood. 

 Other birds, pigeons, pheasants, sparrows, wild and domestic ducks 

 are also susceptible to the disease, and rabbits and guinea-pigs can 

 be successfully inoculated ; in the latter animal a local abscess 

 sometimes forms instead of a general infection. By continuous culti- 

 vation with free access of oxygen the virus becomes attenuated, and 

 Pasteur was able thus to prepare a vaccine which protected fowls. 



The bacillus of chicken cholera belongs to the group of hcemor- 

 rhagic septiccemic bacilli (p. 392), and seems to be identical with 

 Koch's bacillus of rabbit septicaemia, and with the bacillus of swine 

 plague (see p. 373). These organisms tend to form a stalactite 

 growth in butter broth. 



Organisms have been described by Klein in fowl enteritis, grouse 

 disease, etc., differing somewhat from the bacillus of chicken 

 cholera. 



Mouse Septicaemia 



This disease may be conveniently described here. Koch first 

 obtained a minute bacillus by injecting putrefying material sub- 

 cutaneously into mice. It seems to be identical with the bacillus 

 found in swine erysipelas. The organisms are met with in large 

 numbers in the blood and tissues of mice. They measure only 

 1 p in length, and occur in considerable numbers in the leucocytes. 

 The bacillus stains well by Gram's method, and is stated by some 

 writers to be motile. It grows readily, forming on agar extremely 

 delicate, almost invisible colonies ; in stab gelatin cultures after 

 some time a delicate cloudiness radiates from the central puncture. 

 From an agar culture the bacilli are somewhat larger than those 

 found in the animal body, and form filaments. It is pathogenic for 

 swine, rabbits, and mice. 



