142 DISEASES. 



cephalus are rare. Cancer and cholera are quite unknown. 

 Small-pox and measles passed through the country about twenty 

 years ago, and committed great ravages ; but, though the former 

 has since broken out on the coast repeatedly, neither disease has 

 since traveled inland. For small-pox, the natives employed, in 

 some parts, inoculation in the forehead with some animal deposit ; 

 in other parts, they employed the matter of the small-pox itself; 

 and in one village they seem to have selected a virulent case for 

 the matter used in the operation, for nearly all the village was 

 swept off by the disease in a malignant confluent form. Where 

 the idea came from I can not conceive. It was practiced by the 

 Bakwains at a time when they had no intercourse, direct or indi- 

 rect, with the southern missionaries. They all adopt readily the 

 use of vaccine virus when it is brought within their reach. 



A certain loathsome disease, which decimates the North Amer- 

 ican Indians, and threatens extirpation to the South Sea Island- 

 ers, dies out in the interior of Africa without the aid of medicine ; 

 and the Bangwaketse, who brought it from the west coast, lost it 

 when they came into their own land southwest of Kolobeng. It 

 seems incapable of permanence in any form in persons of pure Af- 

 rican blood any where in the centre of the country. In persons 

 of mixed blood it is otherwise ; and the virulence of the secondary 

 symptoms seemed to be, in all the cases that came under my care, 

 in exact proportion to the greater or less amount of European blood 

 in the patient. Among the Corannas and Griquas of mixed breed 

 it produces the same ravages as in Europe ; among half-blood 

 Portuguese it is equally frightful in its inroads on the system ; 

 but in the pure Negro of the central parts it is quite incapable of 

 permanence. Among the Barotse I found a disease called manas- 

 sah, which closely resembles that of the foeda mulier of history. 



Equally unknown is stone in the bladder and gravel. I never 

 met with a case, though the waters are often so strongly impreg- 

 nated with sulphate of lime that kettles quickly become incrust- 

 ed internally with the salt ; and some of my patients, who were 

 troubled with indigestion, believed that their stomachs had got 

 into the same condition. This freedom from calculi would appear 

 to be remarkable in the negro race, even in the United States ; for 

 seldom indeed have the most famed lithotomists there ever oper- 

 ated on a negro. 



