INSECTS INJURIOUS TO CATTLE 413 



ficult; (2) it is claimed that the oil in the coat tends to 

 protect from storms of snow, rain, and sleet; (3) the oil 

 tends to cause an early shedding of the hair. In the 

 late autumn, in climates where changes are sudden, 

 there is hazard in spraying thus, insomuch that serious 

 loss has been known to result therefrom. The materials 

 thus used should be effective in treating small lots, pro- 

 viding the water and oil could be kept properly stirred. 

 Notwithstanding the efficiency of this method of treating 

 mange, it will be manifest that for some time to come, 

 owing to the magnitude of the work, dipping will still 

 be done in large measure by means of vats and by the 

 various formulas outlined by the United States Depart- 

 ment of Agriculture. 



Southern or Texas fever. — This disease, more com- 

 monly known as Texas fever, is so designated doubtless 

 because of the extent to which it was carried to cattle 

 in the states northward by natives drafted from Texas 

 to graze on the ranges. It is called southern fever, be- 

 cause its settled home is in the South, since it cannot 

 survive the cold of the northern winter. It is also known 

 by such names as Spanish, acclimation, splenic or tick 

 fever, red water, bloody murrain, and town-cow disease. 



Texas fever is caused by a microscopic animal germ, 

 Pyrosoma biglminiim, which lives within the red cor- 

 puscles of the blood and breaks them up, usually, but 

 not always, with great rapidity. When the destruction 

 is rapid the disease is present in the acute form, and it 

 is fatal. When the destruction is slow, it is present in 

 a mild form, which is not usually fatal. All the disease 

 processes in Texas fever result from the red corpuscles 

 of the blood. 



The disease is transmitted, as it were, indirectly. It 

 is communicated by means of the southern cattle tick 

 (Boophilus anntdatus), and indirectly as shown below. 

 This is the only known medium of communication. 

 Animals which sicken and die from it do not directly 



