PROWAZEKIA ASIATICA 65 



binary fission. The organism can encyst (fig. 25, a), when the flagella are 

 lost, and round or oval cysts are found, 5//, to 7 yu- in diameter. After 

 a time flagella are formed inside the cyst, and the organism emerges 

 therefrom in its typical flagellate form (fig. 25, b /"). 



Sinton's case is interesting. He obtained the flagellate only twice 

 from the same patient, a Mexican then in hospital in Liverpool. The 

 flagellate was not found in the patient's fasces, nor was it found in 

 the urine on later occasions when taken aseptically. 



FIG. 25. Prowazekia urinarla. Flagellate emerging from cyst. (After Sinton.) 



In cultures Prowazekia urinarla was always found in association 

 with bacteria. The cultures died at a temperature of 37 C., but grew 

 well at 20 C. Various media were useful at the lower temperature, 

 such as urine, salt agar, nutrient agar, serum agar, blood agar, peptone 

 salt solution, and diluted blood serum. The flagellate was, then, 

 considered to be an accidental contamination and not a true parasite 

 of human urine. 



Prowazekia asiatica, Castellani and Chalmers, 1910. 



The flagellate was found by the discoverers in the stools of patients 

 suffering from ankylostomiasis and diarrhoea in Ceylon. It was referred 

 by them to the genus Bodo, but in 1911 Whitmore 1 further studied 

 it and placed it in the genus Prowazekia. In the stools the flagellate 

 is found either as a long, slender form measuring io//, to 16 fju by 5 yu, 

 to 8//, or as a rounded form 8 //, to io//, in diameter. Its cytoplasm is 

 alveolar. A rhizoplast connects the basal granules to the kinetic 



1 Arch. f. Protistenk. xxii, p. 370. 



