836 



Manual of Veterinary 31icrobiology. 



and others, again, attribute the disease to a micro- 

 coccus. We have found as the result of our own 



by Smith by intra-venous and subcutaneous injection of suscep- 

 tible cattle with the blood of animals suffering from the disease 

 as well as with the blood of apj)arently healthy southern cattle. 

 No other animal species has been found to be susceptible. Direct 

 contagion seems, however, rarely or never to occur under natural 

 conditions. 



Microbe.— Cover glass preparations from the blood, spleen, liver, 

 kidney, and heart muscle of cattle which have died from acute 

 Texas fever, show the presence of a rounded or somewhat ovoid, 

 or pyriform (Smith) body, isolated, in pairs, or occasionally three 

 or four, within a certain proportion of the red blood corpuscles. 

 They are usually extremely abundant in the juice of the kidney 

 (where they also occur between the cellular elements), less so in 

 the liver and spleen, and still less in blood from the large ves- 

 sels or heart. These stain readily with aqueous solutions of ani- 

 line colors (methylene blue), as well as with hsematoxylin (Dela- 

 field's). Their outline after staining is generally less well defined 



than bacteria 

 similarly stain- 

 ed ; neverthe- 

 less their ap- 

 pearance with- 

 in the unstain- 

 ed disk of the 

 red blood cells is 

 quite character- 

 istic and in the 

 absence of other 

 evidence is of 

 itself sufficient 

 for a diagnosis 

 of the disease. 



Culture tests of 

 the blood and 

 organs in cases 

 of Texas fever 

 have, in gener- 

 Billings obtained an ovoid " bi-polar " 



oo 



Smear preparation from kidney of ox. 

 Texas Fever. XIOOO. (D.) 



al, led to negative results. 



Acute 



