506 DISEASES OF CATTLE. 



markets. In addition to this, the increase in prices of cattle sold 

 locally in the South would represent a large sum. This local increase 

 has already been found to amount to from $3 to $15 a head in tlie 

 territory recently freed from ticks. An agricultural official of one 

 of the Southern States reports that calves in the tick- free area bring 

 just double the prices that can be obtained for similar calves in the 

 tick-infested region. 



Heretofore it has been impracticable to improve the quality of 

 southern cattle by introducing fine breeding animals from other sec- 

 tions, because such animals were liable to contract Texas fever and 

 die unless protected by inoculation. Furthermore, it is impossible 

 for animals to attain good growth and to thrive when they are 

 heavily infested with ticks. With the eradication of the ticks, how- 

 ever, the southern farmers are enabled to introduce good breeding 

 animals and to improve the grade of their stock. 



There is no longer any doubt that it is entirely practicable to 

 exterminate the ticks throughout the entire region, and the accom- 

 plishment of this result will be of tremendous economic advantage 

 not only to the South but to the whole country. The rate of progress 

 depends mainly on two factors — the amounts appropriated by the 

 Federal and State Governments, and the cooperation of the people. 



CHRONIC BACTERIAL DYSENTERY. 



Chronic bacterial dysentery is a chronic infectious disease of 

 bovines caused by an acid-fast bacillus simulating the tubercle 

 bacillus and characterized by marked diarrhea, anemia, and emacia- 

 tion, terminating in death. 



Eecently this disease has been observed in the United States for 

 the first time by Pearson in Pennsylvania cattle, and later by Mohler 

 in Virginia cattle, and in an imported heifer from the island of 

 Jersey at the Athenia quarantine station of the Bureau of Animal 

 Industry. 



The former has proposed the name chronic bacterial dysentery for 

 this affection, and it has also been termed Johne's disease, chronic 

 bacterial enteritis, chronic hypertrophic enteritis, and chronic bovine 

 pseudotuberculosis enteritis by various European investigators. The 

 disease w^as first studied in 1895 by Johne and Frothingham in Dres- 

 den, but they were inclined to attribute to the avian tubercle bacillus 

 the cause of the peculiar lesions of enteritis which they observed. In 

 1904 Markus reported this disease in Holland, and subsequently it 

 was observed in Belgium, Switzerland, Denmark, and Great Britain. 



Cause. — The bacillus, which has been invariably demonstrated in 

 the intestinal lesions and mesenteric lymph glands in this disease, is 

 a rod about 2 to 3 microns long and 0.5 micron wide. It stains more 

 or less irregularly, like the tubercle bacillus, and moreover the simi- 



