140 TROPICAL MEDICINE AND HYGIENE 



should be inserted half an inch from the middle line and 

 steadily pushed inwards and slightly upwards, till it is 

 felt to pass through the tough membrane. If it strikes 

 the bone the needle should be partly withdrawn, and 

 then directed slightly more downwards. The escape of 

 clear fluid will render it certain that the point of the 

 needle is in the canal. 



Prognosis. The terminal stage, sleeping sickness, is 

 invariably fatal. The earlier stages of the disease, when 

 there is merely a trypanosome infection of the blood and 

 lymphatic system, are often amenable to treatment, and 

 there is good reason to believe that complete and per- 

 manent recovery may ensue. 



The disease is a serious one, and the prognosis, even 

 when all the symptoms have disappeared and the 

 parasites cannot be found in either glands or blood, 

 must be guarded, as cerebrospinal symptoms may occur 

 years after the original infection. The prognosis is worse 

 in the Rhodesian variety and in all cases that do not 

 yield readily to moderate doses of atoxyl. 



Pathological Anatomy. Little is known of the patho- 

 logical anatomy of the early stages of the disease in man. 

 In monkeys and the lower animals the condition is mainly 

 one of visceral congestion, but enlargement of the spleen 

 and intense congestion, sometimes haemorrhagic, of the 

 lymphatic glands and extreme congestion of the brain are 

 also met with. Similar changes occur in the liver. 



In sleeping sickness there is formation of round cells in 

 the perivascular spaces of the cerebral capillaries, closely 

 resembling that found in general paralysis of the insane. 



Treatment. The drugs most distinctly useful in malaria, 

 quinine and methylene blue, have no effect in this disease, 

 and do not alleviate the symptoms or reduce the number 

 of trypanosomes. Arsenic long had some reputation 

 in the treatment of the early stages of sleeping sickness, 

 and experiments with various trypanosome infections in 

 lower animals showed that this drug had a decided 

 controlling effect, and that the number of parasites could 



