ETIOLOGY 343 



farciminosus) . This affection has been recognized at different 

 times in Japan, China and India. It has been known in 

 Algiers for many years and during the war in South Africa it 

 seems to have been introduced there. From South Africa it 

 has been imported into England and Ireland by government 

 horses returning from the Cape. The first case in England 

 appears to have been detected in 1902. In 1907, Pearson dis- 

 covered it in western Pennsylvania. 



§ 256. Etiology. This disease is caused by an organism 

 described by Rivolta as Saccharomyces farciminostis. It is also 

 called a cryptococcus. According to Pallin, it is found in 

 large numbers in the diseased tissues and products, partly 

 free and partly enclosed in pus corpuscles, which often con- 

 tain from ten to thirty or more of them. It is characterized 

 by its clearly defined contour and its very refractile double 

 outline. It measures from 3 to 4 yu in diameter, and in the 

 unstained preparations it is said to be best seen with an oil 

 immersion and abbe condenser, under a magnification of not 

 less than 800 diameters. In stained preparations it can be 

 recognized with a much lower magnification. 



The classification of this organism has been much dis- 

 cussed by several workers. Canalis places it with the coccidia, 

 Plana and Galli-Valerio consider it as belonging to the proto- 

 zoa, and Formi and Aruch as a blastomycete. Tokishige 

 and Marconi believe that it belongs with the saccharomyces. 

 It is not easily stained by the aniline dyes, although Mettam 

 has shown that by the Gram method, Nicolle's violet, Nicolle's 

 thionine and others it is readily colored. It is cultivated with 

 difficulty. Tokishige obtained cultures in bouillon, agar, 

 gelatin and on potato. In bouillon it required seventeen days 

 to obtain a growth. 



The infectious material may be transported by contact 

 between the diseased and well horses, by stall bedding, by 

 stable utensils and harnesses and possibly by insects. 



The period of inaibation \s placed at from three weeks to 

 three months and in certain cases it may extend to even eight 



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