SYMPTOMS 197 



produces spores. In cultures long involution fornis^are often 



observed. It is anaerobic and consequently will^not develop 



in the presence of air. In suitable culture media under anaerobic 



conditions or in animal tissues (other than blood) itnuultiplies 



rapidly with the evolution of gas. The 



presence of spores renders it very resistant ^ ^ 



to natural destructive agencies and to the © ^ if 



common disinfectants. The bacillus of black j a /^ ® 



quarter or its spores are supposed to gain - ^ ^ f ssza 

 entrance to the tissues of animals through 

 abrasions of the skin or, possibly, the mucous 

 membranes of the mouth or intestine. Fig. 43. Ba- 



§155. Symptoms. Black quarter runs cillus of symptoma. 

 a rapid course and usually ends fatally in • 

 from one to three days. The first symptoms may be either 

 general or local in character. Arloing, Cornevin and Thomas 

 believe that general symptoms always precede the local mani- 

 festations. Norgaard reports finding cattle with marked local 

 lesions but few animals suffering from general symptoms al- 

 though the latter may have preceded the former and have 

 subsided. 



The general symptoms are elevation of temperature, 

 which usually falls to the normal or even subnormal before 

 death, loss of appetite, loss of rumination and pronounced 

 depression. Respiration becomes accelerated, the animal 

 moves with difficulty and lies down frequently. At first the 

 visible mucous membranes are congested and within twelve to 

 fifteen hours they have a dirty leaden or purplish color. 



The local symptoms may appear on different parts of the 

 body except below the knee or hock joints and on the tail. 

 They are less frequently found about the head. They usually 

 appear on the thighs, neck, shoulders and lower region of the 

 chest. The swelling is at first small and painful. It spreads 

 rapidh' and may in a few hours attain to a large size when it 

 becomes characterized by a crackling and gurgling sound 

 when the hand is passed over it. On percus.sion it gives a 

 clear, tympanic sound due to the collection of gas in the 

 affected tissues. At the center of the larger swellings the 



