4o6 



SURRA 



period, or by a slow convalescence. During this stage usually within 

 10 days after the onset, there appears a commencing CEdema above the 

 belly, involving the soft parts, coincident with this, or soon after, the 

 oedema extends to the feet and legs. The pulse becomes rapid, weak 



Fig. 107. Photograph of blood of horse coniaining Trypanosoma. 

 Taken by Smith and Kinyoun. 



and dichrotic, the respiration increased, shallow and jerky, the gait 

 staggering. Emaciation is rapid and extreme. 



" The disease has a tendency to relapse, this may occur at any time, 

 even after convalescence appears to have been fully established. The 

 relapses are invariabh' fatal. 



"The mortality in this epidemic has been about 75 per cent for 

 American horses and mules, and 100 per cent for native ponies. 



" The gross pathology shows serous effusions into the pleurse, peri- 

 cardium, and sometimes the peritoneum. There is also a serous exudate 

 into the cellular tissue of the legs and abdomen. The organs are pale, 

 but otherwise normal in appearance. 



" At the time of our inspection, five acute cases were examined, the 

 duration of the attack being from six days to two weeks. All these 

 animals presented the several clinical appearances as above described. 



"Blood specimens were taken from the jugular vein of each and 

 examined microscopically, shortly afterwards. In 4 of these a parasite 



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