164 THE KINGDOM OF MAN 



medical men who have had it under observation have 

 given a proper anatomical account of it. It appears that 

 this worm is very common in the blood of negroes in 

 tropical Africa ; and as it was found in several cases in 

 the blood of individuals attacked by sleeping sickness, Sir 

 Patrick Manson was justified in entertaining the view 

 that this parasite was the cause of the disease. 



One of the first results obtained by the commission 

 sent by the Royal Society committee to Uganda was the 

 proof which had, indeed, been already furnished by the 

 resident medical officers of the Uganda Protectorate that 

 Filaria perstans, though remarkably abundant in the 

 blood of the negroes of Uganda, can have nothing to do 

 with sleeping sickness, since, though it often occurs in 

 persons attacked with that disease, it also exists in districts 

 where sleeping sickness is unknown ; and, further, many 

 cases of sleeping sickness have been observed in which no 

 Filaria perstans has been discovered in the blood or other 

 parts of the body. 



While Drs. Low and Christy occupied themselves with 

 settling this question as to the connexion of Filaria 

 perstans with the disease and carried out a careful study 

 of its clinical aspects, Dr. Castellani examined the brain 

 and spinal cord of those who died from sleeping sickness, 

 for bacteria. He found again and again an extremely 

 minute globular vegetable parasite of the kind known as 

 streptococcus which he concluded to be the cause of the 

 disease, although he had not produced the disease experi- 

 mentally by inoculating an animal with this microbe. 



In the early part of 1903 these were the only results 

 obtained by some six months' work of the medical men 

 sent out by the Royal Society's committee ; and it was 

 felt that something more must be done. The investigation 

 of a disease hitherto little known and studied is one of 



