INFECTIOUS DISEASES. 577 



10 to 14 dajs, the only sign left of the former swelling is a slight 

 thickening of the skin over the point of the injection; but at the 

 moment when the tension and tenderness of the parts at the seat 

 of inoculation become suddenly decreased a symptom of the utmost 

 clinical importance takes place, namely, at that moment the parasite 

 of surra enters the blood of the general circulation. 



The temperature on the day of inoculation, and, in fact, for several 

 days afterwards, may remain normal in character, there being only 

 a few degrees difference between the morning and evening observa- 

 tions. In other cases there may be a slight rise from the first even- 

 ing, and a gradual progressive rise until the swelling at the seat of 

 inoculation shows signs of reduction in size, when the temperature 

 generally takes a decided rise again, and may attain 104° or 105.8° F. 

 This elevation will last a varying period of from two to six days, 

 and on the day following its onset the ordinary symptoms of fever 

 will be noticed, and in addition there will be petechise on the con- 

 junctival membranes, lacrimation, a slight mucous discharge from 

 the nose, and in severe cases some edema of the lower portion of the 

 legs, and perhaps of the sheath in horses.' At the termination of the 

 period of fever the temperature will be found to have fallen to nor- 

 mal or nearly so; the animal will present a brighter aspect, and 

 there is every appearance of its return to health; in a few days, 

 however, the animal again appears dull and half asleep; the tem- 

 perature is elevated, a relapse takes place, and a repetition of all the 

 symptoms in the primary paroxysm, including the reappearance of 

 the parasite, is observed. 



Diagnosis. — ^A diagnosis may also be established by the comple- 

 ment-fixation or agglutination tests with the sera from suspected 

 animals. This, however, can be carried out only in laboratories and 

 requires special facilities for its execution. 



Treatment. — No satisfactory treatment is known. Intravenous in- 

 jections of Fowler's solution of arsenic give temporary relief, but re- 

 lapses occur. In view of the great economic importance of this 

 disease, it would not be advisable to attempt to treat any sporadic 

 cases should they occur in this country. On the contrary, the animals 

 should be slaughtered immediately and their carcasses promptly 

 burned. 



36444°— 1&— 37 



