472 NOTES ON PARASITES IN EAST AFRICA 
and this is borne out by the 6*8 per cent, for S. Mansoni for 
the Wa-Kamba. 
The Wa-Giriama — following figures not included in this 
paper — are also infected : probably very heavily, for of 
eighteen porters sent for physical examination, who appeared 
to be in good health, a history of previous hsematuria was 
obtained from nine ; and of four of these, who also stated that 
they could pass blood at the time, and which was done, the 
terminal-spined ova of S. hcematobium were demonstrated 
in all. 
On the other hand, the high figures for the tapeworm 
infections — almost all T. saginata — are due, I believe, to the 
personal habits of the natives of certain tribes — i.e., the Wa- 
Kavirondo, Kikuyu, and Kisii — w T ho do not cook their meat 
sufficiently, but eat it practically raw, and their results are 
therefore correspondingly raised. 
Variations in the distribution of the various infections 
are thus not only dependent upon geographical, climatic, 
and seasonal conditions, but likewise on the tribal and in- 
dividual habits of the native. 
Parasitic human helminthiasis occupies an important 
position in its bearing on the question of native labour, more 
especially with reference to its relationship to the inefficiency 
and mortality which occur whenever such labour is con- 
centrated on works, whatever they happen to be. 
From the administrative outlook the problem for the 
present must apparently confine itself to the practical sanita- 
tion of townships, stations, and areas, necessarily circumscribed 
and selected, on which native labourers are employed in 
large numbers. 
Expenditure incurred for such special and temporary 
reasons, and directed towards the attainment of immediate 
results, is not only justifiable but economic. 
No ultimate and permanent results could be anticipated 
with reasonable expectation of success were the same principle 
to be applied to large areas, except at an entirely prohibitive 
cost, unless there were at the same time a decided advance- 
ment in the standard of education and civilisation of the 
native. 
