DIFFERENTIATION 429 



1. "The same animals are susceptible to both diseases — 

 the horse, ass, mule, goat, sheep, cow, camel, dog, cat, 

 monkey (long- tailed macayo), rabbit, guinea-pig, and rat. 



2. "In the horse the course of the disease is the same, 

 whether surra or nagana. The animal dies at the same time, 

 in 30 days on the average. In inoculation cases the period of 

 incubation is the same, and the same symptoms and lesions 

 supervene. 



3. "The other equides, the goat, sheep and dog, die of 

 the two diseases in the same length of time and with similar 

 symptoms and lesions. 



4. "Rabbits, guinea-pigs and rats succumb to the infec- 

 tion in a like manner. 



5. "Cows rarely survive nagana, and they rarely die 

 from surra. They become emaciated with surra but recover 

 in health and a subsequent inoculation does no harm. This is 

 a marked difference between them but it may be explained 

 when further experiments are made." 



Laveran and Mesnil believe that the paralysis of the pos- 

 terior extremities, a marked symptom in mal de caderas , is less 

 marked in surra and nagana, although they believe the three 

 affections very closely related. Dourine differs from the other 

 three in two distinct points : ( i ) The morphology of the para- 

 site is different. (2) In dourine contagion by coition seems 

 to be the only natural mode of infection. 



Much additional investigation will be necessary before 

 the question of either the identity or the non-identity of these 

 affections can be positively determined. As these diseases 

 are not liable to become of great economic importance in this 

 country, further discussion of the voluminous literature seems 

 unnecessary. , 



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