INFECTIOUS DISEASES. 575 



gradually disappear during the period of apyrexia. After the fever 

 and the accompanying symptoms have for the second time been 

 present for a few days— the period varying f;:om one to six— the 

 animal is found to have lost the dull, dejected appearance and to 

 look bright. The temperature has fallen and, in some cases, has 

 attained normal or even subnormal limits. The visible mucous mem- 

 branes are clean, and the conjunctival petechise begin to fade; the 

 pulse, however, will be found to be weak and thready in character, 

 but the appetite excellent, and, in fact, if it were not for the loss of 

 flesh and slight edema of the legs, there would be little to show that 

 the animal was sick. Unfortunately, however, this condition does 

 not continue for any great length of time, for again the temperature 

 is elevated ; in the course of a few hours the thermometer registers 

 a still higher degree, the animal is dull and dejected, and by the 

 following day the visible mucous membranes present a yellow tinge ; 

 large ecchymoses, dark in color, appear on the conjunctival mem- 

 branes, the action of the heart is irritable, the pulse full and quick, 

 or at times intermittent, and regurgitation may be observed in the 

 jugulars, the breathing is quickened, and the individual respirations 

 are shallow. On watching an animal in this condition it may be 

 noticed that it takes seven or eight very short inspirations, followed 

 by a much more prolonged and sonorous one; at the same time the 

 breathing is more abdominal than thoracic in character. On exami- 

 nation of the legs it will be found that the swelling and edema have 

 increased considerably, and that on the under surface of the abdo- 

 men, where previously it was confined to the sheath, it has now com- 

 menced to spread forward along the subcutaneous tissue between the 

 skin and the muscles. During the whole of this time the appetite 

 will have varied little, and the evacuations will be only slightly, if 

 at all, altered in character. In the blood a repetition of the previous 

 events takes place, the parasites make their appearance and increase 

 to a maximum and again suddenly or gradually disappear, according 

 to the length of the fever period. These periods, alternating with 

 and without fever, may go on for a considerable time. The pro- 

 gress of the disease is variable and greatly depends upon the con- 

 dition of the animal attacked, the weak one succumbing very rapidly, 

 but each return of the fever brings with it, as a rule, an increase in 

 the severity of the symptoms. There is increased yellowness of the' 

 membranes, fresh crops of petechise on the conjunctiva, a collection 

 of gelatinous material at the inner angle, which at times becomes red 

 in color from an admixture of blood, and which on microscopic ex- 

 amination is found to contain a varying number of the surra para- 

 sites; increased swelling and edema of the extremities and abdomen, 

 which now extends between the fore limbs and up the chest. During 



