192 DISEASES DUE TO PROTOZOA 



an enlargement of which is an early sign of infection. When 

 the disease is well settled we see progressive anemia, weakness, 

 and sleepiness, whence comes the name " sleeping sickness." 

 The end comes from profound anemia and prostration. 

 Pains and dropsical collections are common. The disease 

 lasts a varying time. The early stages are slow, but when the 

 great depression begins it usually progresses rapidly to a fatal 

 end. The changes produced are those of obstruction to the 



FIG. 61. Trypanosoma gambiense. (From Calkins. Preparation by 

 F. W. Balstack.) 



lymphatic system and low-grade chronic inflammations. The 

 microorganisms are present in the blood, all organs, including 

 the lymph glands, and the cerebrospinal fluid. From all 

 these places they may be recovered in making a diagnosis. 

 Trypanosomas are irregular, elongated, twisted bodies with 

 a large nucleus variously placed, and a thickened ribbon- 

 like edge, the undulating membrane, which starts as a minute 

 secondary nucleus at the hind extremity and ends in a rather 

 long whip-like flagellum at the fore end. They range from 



