INFECTIOUS DISEASES OF CATTLE. 483 



finest bile canals and chokes these up completely. This in turn inter- 

 feres with the nutrition of the liver cells and they undergo fatty de- 

 generation and perish. The functions of the liver are thereby com- 

 pletely suspended and death is the result. This enormous destruc- 

 tion of corpuscles takes place to a large extent in the kidneys, where 

 a great number of corpuscles containing the parasites are always 

 found in acute cases. This accounts largely for the blood-colored 

 urine, or red water, which is such a characteristic feature of Texas 

 fever. The corpuscles themselves are not found in the urine; it is 

 the red coloring matter, or hemoglobin, which leaves them when they 

 break up and pass into the urine. 



Syinpto7ns. — After a period of exposure to infected soil, which may 

 vary from 13 to 90 days, and which will be more fully discussed 

 further on under the subject of cattle ticks as bearers of the Texas- 

 fever parasite, the disease first shows itself in dullness, loss of appe- 

 tite, and a tendency to leave the herd and stand or lie down alone. A 

 few days before these symptoms appear the presence of a high fever 

 may be detected by the clinical thermometer. The temperature rises 

 from a normal of 101° to 103° F. to 106° and 107° F. There seemis 

 to be little or no change in temperature until recovery or death en- 

 sues. The period of high temperature or fever varies considerably. 

 As it indicates the intensity of the disease process going on within, 

 the higher it is the more rapid the fatal end. When it does not 

 rise above 104° F. the disease is milder and more prolonged. 



The bowels are mostly constipated during the fever; toward the 

 end the feces may become softer and rather deeply tinged with bile. 

 The urine shows nothing abnormal during the course of the disease 

 until near the fatal termination, when it may be deeply stained with 

 the coloring matter of the blood. (Hemoglobinuria ; see PI. XLVII, 

 fig. 3.) Although this symptom is occasionally observed in animals 

 which recover, yet it may generally be regarded as an indication of 

 approaching death. The pulse and respiration are usually^ much 

 more rapid than during health. 



Other symptoms in addition to those mentioned have been de- 

 scribed by observers, but they do not seem to be constant, and only 

 the above are nearly always present. As the end approaches emacia- 

 tion becomes very marked, the blood is very thin and watery, and the 

 closing of any wound of the skin by clots is retarded. The animal 

 manifests increasing stupor and may lie down much of the time. 

 Signs of delirium have been observed in some casas. Death occurs 

 most frequently in the night. 



The course of the disease is very variable in duration. Death may 

 ensue in from three days to several weeks after the beginning of the 

 fever. Those that recover ultimately do so veiy slowly, owing to 

 the great poverty of the blood in red corpuscles. The flesh is re- 

 gained but very gradually, and the animal may be subjected to a 



