488 PROTOZOA 



sionary's wife who had resided on the Upper Congo for a year. She 

 presented the same group of symptoms as Button's case, and after 

 repeated examinations trypanosomes were found in her blood. Manson 

 soon after published a similar case. Broeden has published 2 more 

 cases and recently Baker has reported 3 cases among human beings. 



Of these 16 cases of trypanosomiasis in man, 2 were apparently 

 healthy persons, 6 had malarial fever as well, and 8 were such as 

 showed clinical symptoms apparently entirely due to the infection with 

 trypanosomes. 



Quite recently Castellani has stated that the cause of sleeping sick- 

 ness of the negro is a trypanosome. He found trypanosomes in the 

 centrifugalized cerebrospinal fluid of 20 out of 34 cases of this disease. 

 His work has been corroborated by Bruce, Nabarro, Greig and others. 

 Bruce found trypanosomes in the fluid obtained by lumbar puncture in 

 all of the 38 cases examined and in 12 out of 13 cases in the blood. The 

 trypanosomes found in these cases resemble those found in other human 

 beings, and probably belong to the same species. Laveran and Mesnil 

 recommend the names trypanosoma Gambiense Button for the para- 

 site and human trypanosomiasis for the disease. 



Sleeping sickness, or human trypanosomiasis, is a disease of the negro, 

 endemic in certain regions of equatorial Africa. Neither age nor sex 

 are predisposing factors, but occupation and social position seem to 

 have a marked influence, the great majority of the cases occurring 

 among very poor field workers. As these workers are all negroes, the 

 question of the influence of race cannot be determined. The white 

 race, however, is not immune, as has been shown by the cases quoted 

 above. 



In places where most of the cases occur, a fly belonging to the species 

 glossina (Glossina palpatis) is very abundant ; in places where this fly 

 is not found no cases occur. Hence, it is highly probable that, as 'in 

 the trypanosomiasis of the lower animals, the contagion is spread by a 

 biting insect. 



Symptoms. The course of the disease is very insidious, as the try- 

 panosomes may exist in the blood for a long time before entering and 

 growing in the cerebrospinal fluid and causing the characteristic symp- 

 toms of sleeping sickness. Therefore, the symptoms may be divided 

 into two stages. In the first stage there is only an irregular fever. In 

 the second stage the fever becomes hectic, the pulse is constantly in- 

 creased; there are neuralgic pains, partial cedemas and erythemas, 

 trembling of the muscles, gradually increasing weakness, emaciation, 

 and lethargy. The somnolence increases until a comatose condition is 

 developed and death occurs. In the second stage trypanosomes are 

 always found in the cerebrospinal fluid. Throughout the disease they 

 are usually found in small numbers in the blood. 



Duration. The first stage may last for several years; the second, 

 from four to eight months. The percentage of deaths in cases reaching 

 the second stage is 100. Whether some in the first stage recover is not 

 yet certain. 



