SOUTHERN FEVER 261 



where the disease did not break out for months, and others where it 

 occurred in one to two days, or occupied only a few hours. These 

 differences are probably due to the number of the parasites in the 

 system, and the reaction of the affected individuals to the poison, or to 

 varieties at present unknown in the stages of the parasite outside the 

 body. 



SOUTHERN OR TEXAS CATTLE FEVER. 



(Ixodic Anaemia in Jamaica, Williams. Australian Tick Fever.) 



This disease is due to the ravages of a blood parasite, the 

 'Pyrosoma bigeminum, ' originally discovered by Smith in the red 

 blood-corpuscles of cattle affected with southern fever. Williams 

 found it in Jamaica, and Koch has also recently discovered it in 

 Africa, in cattle diseases associated with the presence of ticks (Ixodes 

 or Boophilus bovis). 



The disease affecting cattle, known as Texas or Southern fever, 

 commences with a high fever, which, unless death occurs sooner, 

 lasts about a week, and is associated with severe anaemia and 

 haematuria; a chronic condition often follows when the symptoms 

 are not so exaggerated. 



Microscopical Appearances of the Parasite. When the blood of 

 an affected animal is examined in the fresh state at ordinary temperature, 

 small bodies are seen inside the red blood-corpuscles. These may be pale 

 rounded masses with amoeboid movement and distinct contour, or pear or 

 spindle-shaped bodies, distinctly outlined, with a granular body or vacuole 

 at the thick end. There may be two of the pear-shaped bodies with 

 narrow ends opposed in a single corpuscle. Very rarely three or four 

 ovoid forms occur in the same corpuscle (see Photomicrograph, Fig. 99). 

 The bodies measure from J to 2 /u, in diameter, and are usually situated in 

 the disc of the red corpuscles. 



The Motility when present may persist for an hour. In the blood 

 circulation the infected cells rarely exceed 1 to 2 per cent., and in some 

 cases in a later stage the parasite may be found free. 



If an animal dies or is killed in the acute febrile stage a great 

 number of infected corpuscles are found in the capillaries of the 

 peripheral circulation. The parasites are most plentiful in the vessels of 

 the kidney, next in the liver (see Photomicrographs, Figs. 99 and 100), 

 spleen, and heart substance. 



Staining Reactions. Cover-glass specimens heated after Ehrlich's 

 method, and stained with alkaline methylene blue one-half to two 

 minutes, washed with water, and placed in a 1 per cent, solution of acetic 



