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AGRICULTURAL BACTERIOLOGY 



tion of sodium arsenite, which destroys the tick without 

 injuring the animal. The animals are dipped every two 

 weeks from March to November. If the work is carefully 

 and systematically done, the area in which all animals have 

 been dipped will be free from the tick and will no longer be 



Fig. 53. Texas Fever 



The heavy black line bounds the area in which the disease-transmitting tick 



was present in 1906. The white areas below this line have been freed from the 



tick and the disease between 1906 and 1918 



under the burdensome regulations that so hamper the tick- 

 infested areas. 



The total area rendered free from the tick since the be- 

 ginning of the work in 1906 to December, 1918, embraced 

 458,529 square miles. It seems reasonably certain that 

 within a few years Texas fever will be eradicated from this 

 country. The work of eradication should progress rapidly 

 when the stockmen realize the great economic advantages 

 that will accrue to the industry from the eradication. 

 Texas fever is a disease the eradication of which simply 

 awaits the practical application of knowledge already ac- 

 quired ; while, in the case of other important communicable 



