212 
Bilharziosis in South Africa 
Though I have constantly traced the Bilharzia ova from the bladder 
up the ureters to hilum of the kidney, it would seem that it is 
comparatively rare for the kidneys themselves to be affected by the 
disease in its acute stage, the ova not being found in the substance of 
these organs in large numbers. But the kidney is sometimes markedly 
affected secondarily to the pathological changes in the bladder and 
ureters. There are three main causes inducing kidney changes: (1) as 
the coats of the bladder become thickened they tend to cause a partial 
occlusion of the lumen of the ureters passing between them ; (2) the 
deposit of coffee-ground material already described, at the lower end of 
the ureters, reduces their lumen; (3) the thickening of the coats of 
the ureters has the same effect. 
These three conditions retard the urine from entering the bladder, 
and set up a back pressure, which eventually causes hydronephrosis and 
later pyonephrosis, in some cases to such a degree that after death the 
kidneys are found to be mere shells. The following table shows the 
number of times, in 420 autopsies, in which there were cysts in the 
kidneys or the calices were dilated. 
TABLE IV. 
Tribe Number examined 
Cystic kidney 
Per cent. 
Nyassa 
36 
0 
o-o 
Mozambique 
160 
15 
9-4 
Quilimane 
56 
6 
10-7 
Beira 
2 
0 
o-o 
Myambaam 
64 
7 
10-9 
Mtyopi 
24 
0 
0-0 
Shangaan 
38 
1 
2-6 
Tonga 
2 
0 
0-0 
Angoni 
15 
1 
6-7 
Mashona 
1 
0 
o-o 
Basuto 
7 
1 
14-2 
Mxosa and Pondo 
5 
0 
o-o 
Damara 
10 
1 
100 
Total 
420 
32 or 7-6 
I have seen it stated that the kidneys of persons affected with 
Bilharziosis weigh more than the normal. This, one would naturally 
expect to be the case, but my limited figures do not bear the statement 
out, as, out of five cases which I proved microscopically did not contain 
the ova in the bladder, the average weight of the two kidneys was 284'4 
grammes, whereas the average weight per pair of fifty pairs of kidneys 
