^•itj TRAVELS IN AFRICA, 
Independently of the general ill confequence of improper 
iHanagement of the patient, the chief reafon of the extraor- 
dinary fatality of this complaint among the negroes, appears 
to be the thicknefs of the fkin, which refifting the effort of 
nature to protrude the morbid matter to the furfads, tends to 
throw it back into the circulation. A proprietor. of flaves^ who 
was rather anxious for the confervation of his property, than 
fcrupulous in his attachment to religious prejudice, defired 
to inoculate five of them. A ftrong dofe of fenna was a4- 
miniftered as preparative, and they were afterwards reftrained 
as to diet. Three of them had not in the whole forty puftules, 
and foon recovered. The other two fuffered much ^ and the 
eruption, though not confluent, proved fatal to one of them. 
Whether he had caught it before, been improperly treated, or 
whether it was the effecSt of habit of body, was not clear. 
Thefe were of the true negro cafl, called, , FertU^ They were 
all under twelve years of age. 
Guinea Worm. 
The Mohammedans of Fur, and the Arabs, call the idola- 
ters in their neighbourhood Fertit^ a cj^i Improbus fuk). 
The difeafe called the Guinea Worm is known among them by 
the fame name. It is extremely common, and very trouble- 
some to the flavcs, and fometimes to firee perfons. It is by 
fome efteemed contagious, which however is rather furmifed 
than certified. It confifts of a whitifli tumour, at firft hard and 
painful. Often fliews itfelf about the knee, in the flefliy part 
of 
