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The calves that are born of immune cows and live in 

 tick-infested lots or pastures, acquire immunity while 

 joung, by having such a mild attack of the fever that it 

 is not observed. Possibly complete immunity is only 

 acquired by two or more mild attacks that appear as the 

 succeeding broods of ticks inoculate them. 



Some of the calves born of immune cows escape tick 

 infestation, and consequently escape inoculation. When 

 full srrown, or several vears old, thev mav be taken into 

 a tick-infested pasture or the ticks may be brought to 

 them by introducing new cattle into the herd ; then they 

 may die of Texas fever. Many farms in Alabama are 

 tick- free; many town lots are tick-free; parts of many 

 farms and pastures are tick-free; consequently cattle 

 that are bred and raised in such tick-free places are sus- 

 ceptible to Texas fever. Tick-free lots, pastures and 

 farms are so made by keeping all cattle off them for one 

 or more years, by rotation of crops and pastures, by 

 burning the grass, by killing all the ticks on the home 

 cattle, bv stock law all the vear round, and bv introduc- 

 ing no new cattle without first completely ridding them 

 of ticks. Ticks do not travel any great distance (a few 

 feet only), except when upon their host; by themselves, 

 ticks will rarely, if ever, cross a road 60 feet wide. 

 Hence a tick-infested and tick-free farm may be very 

 near each other and remain in that condition, providing 

 cattle and horses are not permitted to go from one farm 

 to the other, except when these farm animals are free 

 of licks. "Records of losses in Alabama of native, South- 

 ern-bred cattle, from Texas fever have been reported to 

 me every year for several years, and I have records of 

 Texas fever occurring in i^labama-bred cattle in every 

 season of the year. Of course the severe and fatal cases 

 occur mostly in hot portions of the year, while most 

 cases that occur in winter are mild. One or two illustra- 



