THE SLEEPING SICKNESSES 



constantly present in the spleen and liver. The bone-marrow may 

 be very cellular, with congested vessels and haemorrhages. 



Stevenson and others have found trypanosomes scattered through the brain 

 substance in no special relation to the capillaries and smaller bloodvessels 

 in animals inoculated with CastellaneUa gambiensis {nigeriensis) and other 

 trypanosomes. 



Symptomatology. — ^The course of the disease may be roughly 

 divided into three stages — -the incubation, the febrile, called also 

 glandular stage, and the cerebral stage. 



Incubation. — ^The duration of the incubation period is not cer- 

 tainly known in man, but may be considerably shorter than was 

 believed by the old authors; probably in most cases it does not 

 exceed two or three weeks, and, according to Martin and Leboeuf's 

 observations in Europeans, it may be even less than ten days. 

 On the other hand, some 

 infected individuals may 

 not show any sign of 

 disease for months, and, 

 it is said, even five or six 

 years. The bite of the 

 infected Glossina gives 

 rise, as a rule, only to 

 very slight local irritation, 

 which quickly subsides, 

 and is often overlooked 

 by the patient. 



Febrile or Glandular 

 Stage. — ^The onset of the 

 disease is characterized by 

 attacks of fever almost 

 constantly associated in 

 Europeans with an ery- 

 thematous eruption. This 

 fever lasts about a week, 

 and disappears, to recur 

 again later for the same 

 or much longer periods. 

 It is generally of an inter- 

 mittent or remittent type. 

 During an attack the 

 pulse-rate and the res- 

 pirations are increased, 

 and there is often enlargement of the liver and spleen, though 

 how much of this may be due to recurrent malaria is not known; 

 the pulse often remain rapid during the apyrexial periods. Neuralgic 

 pains and headache may also be complained of. 



An erythematous eruption is often found on Europeans. It 

 begins, as a rule, with badly defined, pinkish patches, which clear 

 m the centre until a ring is produced; if a portion of the ring fades 



Fig. 639. — Negro Patient in the Late 

 Stage of Sleeping Sickness. 



