BACILLUS ANTHRACIS 111 



the surface of the medium, spreading outwards and downwards until the 

 whole medium is eventually liquefied, and the bacterial mass sinks to the 

 bottom of the tube. 



On Agar Plates the growth is similar to that on gelatine plates, 

 but the colonies are not so compact, and consist of masses of long 

 threads matted together, the growth continuing upwards upon the 

 surface of the medium. 



On oblique surface Agar a greyish-white tenacious coating is 

 formed with thready edges, the condensation water remains clear, or is 

 only slightly clouded. 



Blood Serum is liquefied slowly. 



Bouillon remains clear, but a cloudy sediment is formed. 



Milk is coagulated and afterwards peptonized. 



On Potato it develops as a dry granular whitish covering, more or less 

 limited to the point of inoculation. 



Pathogenesis. Affects man, cattle, sheep, horses, guinea-pigs, 

 rabbits, mice, and swine, and dogs under exceptional circumstances, the 

 primary localization usually being in the throat ; rats are also difficult to 

 infect. In man the disease is named according to the manner of in- 

 fection. 



1. Pustula Maligna. This is the most common form, and is the 

 result of accidental inoculation of a cutaneous wound. 



2. Pulmonary form. Woolsorters' and ragpickers' disease is the 

 result of the inhalation of dust charged with anthrax spores. 



3. Bowel or Intestinal Anthrax. Due to the consumption of meat from 

 anthrax carcases. 



Inoculation into Animals. Portions of a pure culture of the 

 Bacillus anthracis, when introduced into the subcutaneous tissues of the 

 abdominal wall of guinea-pigs or rabbits, cause the death of these 

 animals in forty-eight hours. Little or no change can be observed at 

 the point of inoculation, but the subcutaneous tissue for some distance 

 over the abdomen and thorax will be found oedematous, with small 

 ecchymoses scattered throughout the osdematous portion ; the under- 

 lying muscles are pale in colour. The internal viscera show no marked 

 macroscopical changes, except the spleen, which is enlarged, dark- 

 coloured, and soft. The liver may present the appearance of cloudy 

 swelling. The lungs are red or pale red in colour, while the heart 

 is usually filled with blood. The disease is a true septicaemia, and after 

 death the capillaries throughout the body always contain the typical 

 rod-shaped organisms in larger or smaller numbers. 



Protective Inoculation against anthrax is practised in animals, 

 according to Pasteur's method, with two vaccines prepared from virulent 

 cultures attenuated by cultivation between 42 and 43 C. - 



