PATHOGENIC PROTOZOA OF THE MASTIGOPHORA 437 



appear in the blood ; there may or may not be fever. In the second 

 stage pains in the back, tremors, and drowsiness supervene. 

 Finally, the patient dies in a comatose condition. In this second 

 stage the organisms are present in numbers in the cerebrospinal 

 fluid. The disease appears to be always fatal, but may run a 

 chronic course lasting several years. 



Immunity. No practicable method of immunization has been 

 developed. 



Bacteriological Diagnosis. The organisms are usually scanty 

 in the blood, and centrifugation is necessary to find them. They 

 may usually be demonstrated in the fluid secured by a lumbar 

 puncture. They may also commonly be demonstrated by punc- 

 turing an enlarged lymphatic gland and examining the fluid secured. 



Transmission. One of the tsetse flies, Glossinia palpalis, has 

 been found to transfer the disease. 



Trypanosoma critzi 



Chagas, in 1909, described this organism as the cause of a 

 disease in man called opilacao, and hitherto confounded with 

 ankylostomiasis. It is transmitted by the bite of a bug (Conor- 

 rhinus sp.). This work needs confirmation. 



Trypanosoma calmettei 



Mathis and Leger, in 1909, described a non-pathogenic try- 

 panosome from the blood of the domestic fowl in Tonkin. It 

 occurs but rarely. 



Trypanosomes in Birds 



Trypanosomes have been described from the blood of a great 

 number of wild birds. They are not known to be pathogenic. 



Trypanosoma lewisi 



Chaussat, in 1850, and Lewis, in 1877, noted the presence 

 of a flagellate in the blood of rats. It is so commonly present 

 in the blood of rats in many parts of the world that it has been 

 frequently used in the laboratory for study and demonstration, 

 although its pathogenic properties are almost nil. This trypano- 

 some cannot be transmitted to any other genus of mammals so far 

 as known : even the closely related genera of the rodents are re- 



