440 DISEASES OF CATTLE. 



ANTHRAX. 



Anthrax, or charbon, may be defined as an infectious disease which 

 is caused by specific bacteria, known as anthrax bacilli, and which is 

 more or less restricted by conditions of soil and moisture to definite 

 geographical localities. While it is chiefly limited to cattle and sheep, 

 it may be transmitted to goats, horses, cats, and certain kinds of 

 game. Smaller animals, such as mice, rabbits, and guinea pigs, 

 speedily succumb to inoculation. Dogs and hogs are slightly sus- 

 ceptible, while fowls are practically immune. The variety of domes- 

 ticated animals which it may attack renders it one of the most dreaded 

 scourges of animal life. It may even attack man. Of this more will 

 be stated farther on. 



Cause. — The cause of anthrax is a microscopic organism known as 

 the anthrax bacillus. (See PI. XXIX, fig. 7.) In form it is cylindri- 

 cal or rod-like, measuring -joVf *° rsW inch in length and 2 j^r iuch in 

 diameter. Like all bacteria, these rod-like bodies have the power of 

 indefinite multiplication, and in the body of infected animals they 

 produce death by rapidly increasing in numbers and producing sub- 

 stances which poison the body. In the blood they multiply in num- 

 ber by becoming elongated and then dividing into two, each new 

 organism continuing the same process indefinitely. Outside of the 

 body, however, they multiply in a different way when under condi- 

 tions unfavorable to growth. Oval bodies, which are called spores, 

 appear within the rods, and remain alive and capable of germina- 

 tion after years of drying. They also resist heat to a remarkable 

 degree, so that boiling water is necessary to destroy them. The 

 bacilli themselves, on the other hand, show only very little resistance 

 to heat and drying. It has long been known that the anthrax virus 

 thrives best under certain conditions of the soil and on territories 

 subject to floods and inundations. The particular kinds of soil 

 upon which the disease is observed are black, loose, warm, humous 

 soils, also those containing lime, marl, and clay, finally peaty, swampy 

 soils resting upon strata which hold the water, or, in other words, are 

 impervious. Hence fields containing stagnant pools may be the 

 source of infection. The infection may be limited to certain farms, 

 or even to restricted areas on such farms. Even in the Alps, over 

 3,000 feet above sea level, where such conditions prevail in secluded 

 valleys, anthrax persists among herds. 



Aside from these limitations to specific conditions of the soil, anthrax 

 is a disease of world-wide distribution. It exists in most countries of 

 Europe, in Asia, Africa, Australia, and in our own country in the 

 lower Mississippi Valley, the Gulf States, and in some of the Eastern 

 and Western States. It seems to be gradually spreading in this coun- 

 try and occurs in new districts every year. 



Meteorological conditions also have an important share in determin- 

 ing the severity of the disease. On those tracts subject to inunda- 



