554 DISEASES OF THE HOESE, 



easily digestible feeds. Not infrequently a dirty yellowish tinge of 

 the visible mucous membranes has been observed, in which cases 20 

 grains of calomel in from 2 to 4 drams of aloes in a ball, or 2-dram 

 doses of fluid extract of podophyllin, may be given. Following the 

 subsidence of the fever, a tonic should be administered, composed of 

 the following drugs in combination: 



Arsenious acid grams 2 



Powdered nux vomica do 28 



Powdered cinchona bark do 85 



Powdered gentian root do 110 



These should be well mixed and one-half tablespoonful given at 

 each feed to the affected animal. 



As in the case of all other infectious diseases, the healthy should be 

 separated from the sick horses, and thorough disinfection of the 

 infected stable, stalls, litter, and stable utensils should be carried out 

 in order to prevent the recurrence of the disease. As a disinfectant, 

 the compound solution of cresol, carbolic acid, or chlorid of lime may 

 be used, by mixing 6 ounces of any one of these chemicals with 1 

 gallon of water. One of the approved coal-tar sheep dips might also 

 be used to advantage in a 5 per cent solution (6 ounces of dip to 1 

 gallon of water). The disinfectant solution should be applied liber- 

 ally to all parts of the stable, and sufficient lime may be added to the 

 solution to make the disinfected area conspicuous. 



Investigations are now in progress with a view of producing a 

 vaccine or serum that will protect horses which have been exposed to 

 the disease. 



SXJRRA. 



By Ch. Waedell Stiles, Ph. D. 

 Professor of Zoology, United States Public Health and Marine-Hospital Service. 



Surra is not known to occur in the United States, but it is more or 

 less common in the Philippine Islands and India. It is caused by a 

 microscopic, flagellate animal parasite, known as Trypanasoma 

 evansi, 20 to 30 /* long by 1 to 2 /* broad, which lives in the blood and 

 destroys the red-blood corpuscles. In general, the disease is very 

 similar to, and belongs in the same general class with, tsetse-fly dis- 

 ease, or nagana, of Africa and mal de caderas of South America. 



Surra is a wet-weather disease, occurring chiefly during or immedi- 

 ately after heavy rainfalls, floods, or inundations. 



Surra attacks especially horses, asses, and mules, but it may occur 

 in kerabau, camels, elephants, cats, and dogs, and has been trans-' 

 mitted to cattle, buffaloes, sheep, goats, rabbits, guinea pigs, rats, 

 and monkeys. No birds, reptiles, amphibia (frogs, etc.), or fish are 

 known to suffer from it. It attacks both male and female animals, 



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