Anthrax. 99 



It is thought that the horse fly is one of the chief means 

 by which the disease is spread among the plantation 

 mules of the southern states. 



Symptoms. The disease appears in two types, in one 

 of which there are no external signs of trouble, in the 

 other swellings or carbuncles develop on the surface of 

 the body. The type showing no localization on the sur- 

 face of the body is most common in cattle and sheep, and 

 is due to infection by way of the intestines. "When the 

 organisms have been introduced through a wound, they 

 may develop at the point of introduction, forming a 

 tumor which is at first hard, hot, and painful. It rapidly 

 increases in size and becomes cold and painless due to the 

 death of the tissues. If the tumor is opened a dark tar- 

 like exudate is noted. The tumors may develop in the 

 throat, especially in hogs and dogs. Gangrene often ap- 

 pears in the tumor, due to secondary infection with pu- 

 trefactive bacteria. 



The disease varies widely in its duration. The first 

 animals to die in an outbreak may show no symptoms 

 whatever, but may be found dead in the pasture. Others 

 may show signs of illness for a few hours, and the last 

 animals to die may have had the disease for several days. 

 In the less rapid forms of the disease, the temperature 

 rises to 105-108 F. The animal may be restless, 

 stamping the ground, running about, and at last going 

 into convulsions, which are followed by death. If the 

 lungs are affected, the animal has difficulty in breathing. 

 In case the carbuncles are noted, the duration of the 

 disease is likely to be longer than when the infection is 

 more general. 



Post-mortem examination. The most prominent 

 changes to be noted on post-mortem examination are the 



