304 SLEEPING SICKNESS [CH. 



observed in the blood of a native in the Gambia and therefore 

 Button considered that it was probably a new parasite and 

 gave it the name of Trypanosoma gambiense. In 1902, Button 

 and Todd proceeded on an expedition to the Senegambia in 

 order to make further investigations into the nature of this 

 infection. They came to the conclusion that trypanosome 

 fever, or trypanosomiasis, was in natives a particularly mild 

 disease for many of those whose blood contained the parasites 

 appeared to be in perfect health, and none of them were serious- 

 ly ill. Owing to the fact that these investigators had to 

 travel about, the cases could not be kept under observation for 

 any length of time and the relation between trypanosome fever 

 and sleeping sickness was not discovered. 



In 1901, an epidemic of sleeping sickness broke out in 

 Uganda and the number of cases increased so rapidly that in 

 1902 the Royal Society sent out a Commission to investigate 

 the causes of this outbreak. This Commission composed of 

 Brs Castellani, Christy and Low, arrived in Uganda in 1902, 

 and at once commenced to work on the etiology of the disease. 

 Whilst Castellani was examining the brains and spinal cords of 

 persons who had died of sleeping sickness in the attempt to 

 find the cause of the malady, the other two members of the 

 Commission travelled about and eventually proved that the 

 area of infection was confined to a narrow strip of country 

 surrounding the lake shores and on the islands of Lake 

 Victoria. This restricted distribution had previously been 

 noticed by Hodges, and clearly shewed that there was no 

 relation between sleeping sickness and Filaria perstans, as 

 suggested by Manson, for the areas of infection were quite 

 different. In 1903, Castellani noted the presence of trypano- 

 somes in the cerebro-spinal fluid of patients infected with 

 sleeping sickness, and the same year Bruce and Nabarro 

 arrived in Uganda to continue these investigations. Bruce 

 at once recognised the possibility that this trypanosome might 

 be the cause of sleeping sickness and on further examination 

 Castellani found that 70 per cent, of the cases contained these 

 parasites in the cerebro-spinal fluid. 



The parasite was described under the name of Trypanosoma 



