366 TEXAS FEVHR 



The Experiment Station of that state offers to immunize 

 (free of charge) northern cattle, if the}' are shipped to the 

 state, for its stock raisers. 



In Missouri, Connaway has immunized a few animals with 

 the blood serum from immune (southern) cattle. In Missis- 

 sippi, Robert has tried the serum for both prevention and 

 treatment with somewhat similar results. In Virginia and 

 Oklahoma the disease and its prevention have been studied. 

 In Texas, Francis is immunizing cattle with most excellent 

 results. He has pointed out the value of immunizing 3'oung 

 (2 to 6 weeks old) calves by artificially infesting with ticks. 

 In Australia the problem of immunizing cattle against the 

 effects of the spreading of the cattle tick in order to save their 

 stock from "tick fever" has become a matter of serious con- 

 sideration. Certain European writers claim that immunity 

 can not be permanently induced by artificial injections. 

 Schroeder has shown that the parasite remains virulent in the 

 blood of naturally immunized cattle for from 10 to 12 years. 



The very limited knowledge of the life cycle of the para- 

 site of Texas fever precludes a satisfactory explanation ot the 

 modus operandi in the production of immunity by these various 

 procedures. On this point there is need for much extended 

 investigation. 



REFERENCES. 



1. Babes. Die Aetiologie der seuchenhaften Haemoglobinurie 

 des Rindes. Virchow's Archiv, Jan. 1889, S. 81. 



2. Connaway. Texas fever or acclimation fever. Bulletin No. 

 J/. Mo. State Board of Agriculture, 1897. 



3. Dalrymple, Morgan and Dodson. Texas or southern catile 

 fever. Bulletin ^i- Louisiana Agric. Expt. Station, 1898. 



4. DiNWiDDiE. Some Texas fever experiments. Bulletin No. 20 

 Ark. Agric. Exper. Station, 1893. 



5. Francis and Connaway. Texas fever. Bulletin No. jj. 

 Texas Agric. Expt. Station, 1899. 



6. Gamgee, Dodge, Billings and Curtis. Diseases of cattle in 

 the United States. Report of the Commissioner of Agriculture, Wash- 

 ington, D. C, 1871. 



