SOUTHERN CATTLE FEVER (TEXAS FEVER, TICK FEVER>. 



DESCRIPTION OF PLATES. 



Plate XLIV. Normal spleen and spleen affected by Texas fevei-. 



Fig. 1. Spleen of an acute, fatal case of Texas fever. The narrow end of 



the spleen is here represented. 

 Fig. 2. Spleen of healthy steer. Though the latter animal weighed one-half 



more than the former, the weight of the diseased spleen (6| pounds) 



was nearly three times that of the healthy spleen (2g pounds). 

 Plate XLV. Texas fever. 



Fig. 1. The cut surface of a healthy liver taken from a steer slaughtered 



for beef. 

 Fig. 2. The cut surface of the liver in Texas fever. 

 Fig. 3. Appearance of the urine in an acute, fatal case of Texas fever. 

 Fig. 4. Red corpuscles, magnified 1,000 diameters, containing the parasite of 



Texas fever. This appears as a blue point a near the edge of the 



corpuscle. The blood was taken from a skin incision. The case was 



nonfatal and occurred late in the fall. 

 Fig. 5. Red corpuscles from the blood of an acute, fatal case, 20 hours be- 

 fore death. The Texas-fever microbes a are shown as pear-shaped 



bodies, stained with methylene blue, within the red corpuscles. The 



larger body on the right & is a white blood corpuscle, also stained with 



methylene blue. (Magnified 1,000 diameters.) 

 Plate XLVI. The cattle tick (Margaropus annulatus), the carrier of Texas 



fever. 

 Fig. 1. A series of ticks, natural size, from the smallest, just hatched from 



the egg, to the mature female, ready to drop off and lay eggs. 

 Fig, 2. Eggs, magnified 5 times. 



Fig. 3. The young tick just hatched (magnified 40 times). 

 Fig. 4. The male after the last molt (magnified 10 times). 

 Fig. 5. The female after the last molt (magnified 10 times). 

 Fig. 6. A portion of the skin of the udder, showing the small ticks. From 



a fatal case of Texas fever produced by placing young ticks on the 



animal, (Natural size.) 

 Fig. 7. A portion of the ear of the same animal, sliowing same fnll-growa 



ticks ready to drop off, (Natural size.) 

 Plate XLVII. The cattle tick (Margaropus annulatus) . 



Fig. 1. Dor.sal view of male. (Greatly enlarged. Original.) 

 Fig, 2. Ventral view of male, (Greatly enlarged. Original.) 

 Fig, 3, Dorsal viev/ of replete female. (Greatly enlarged. Original.) 

 Fig. 4. Ventral view of same, 

 Plate XLVIII. Portion of a steer's hide, showiug the Texas-fever tick (MaV' 



gar opus annulatus). (Natural size. Original.) 

 Plate XLIX. Fig. 1. Tick-infestod steer. 



Fig. 2. Dipping cattle to kill ticks. 

 Plate L. Facsimile of poster used to show the difference between cattle of 



similar breeding raised on a tick-free farm in one case and on a ticky 



farm in the other, 

 496 



