234 



Texas fever the micro-parasite appears as a single round 

 body in the red cell near the preriphery or the outer 

 border. Sometimes tliere nmy be two of these round 

 bodies in a single red cell of the blood. Occasionally 

 the small round bodies may appear singly or in pairs in 

 the plasma of the blood. In severe cases that usually 

 occur in hot weather and when the temperature of the 

 animal is high, tliere may be two spindle or pear-shaped 

 bodies in one red cell of the blood. According to Smithy 

 5 to 50 per cent, of the red cells of the blood may contain 

 these micro-parasites — the number of red cells infected 

 will vary with the tyi>e (mild or acute) of the fever. 

 The number of red cells infected will also vary with the 

 different organs from which the boold is taken for micro- 

 scopic examination. Blood from the capillaries of the 

 liver, heart-muscle, and kidneys, contain from 20 to 90 

 per cent, of infected red blood cells; while the blood 

 from the capillaries of skeletal or voluntary muscles 

 and the skin may contain very few (10 per cent, or less) 

 i infected red blood cells. 



Fresh or dried smears of blood may be examined 

 under the microscope. For fresh smears collect a small 

 amount of blood with platinum loop; place it in the cen- 

 ter of a clean cover glass; drop the cover glass, blood 

 side down, upon a clean slide and surround the cover 

 glass with vaseline or paraffine; the mount is now ready 

 for examination under the microscope. In making 

 dried smears, take two clean square cover glasses ; place 

 a small drop of blood (picked up with the platinum loop) 

 on one of the clean squares a little to one side of the 

 center, and with another clean square spread the droplet 

 of blood over the lower cover glass by attempting to 

 scrape off the droplet with one edge of the upper cover 

 glass, holding the upper one in the right hand inclined 

 at an angle of about 20 degrees, with the lower one that 



