256 THOMPSON YATES LABORATORIES REPORT 
There is no doubt that natives attract Anopheles more than Europeans, and their 
presence under the circumstances indicated, attracts infected Anopheles from other 
native huts. Although then, a European house may be well segregated, and there 
may be also no frequenting of the servants' quarters by native children capable of 
infecting the otherwise harmless Anopheles there, yet the native servants form a route 
along which infected Anopheles, from quarters containing children in the neighbour- 
hood, may pass and gain access to Europeans. Further, the native habits permit of 
the constant frequenting of the native servants' quarters bv all sorts of natives from 
the neighbourhood, and especially of women and children. Some chance of the 
infection of the otherwise harmless Anopheles of the servants' quarters is thus possible. 
The ideal arrangement for the quarters of native servants is then such as 
will permit of one or two of them sleeping close to the Europeans — to be within 
call and to render assistance if necessary — and the others to be relegated to special 
huts of their own at a distance of about half-a-mile. From our observations in 
West Africa this could be easily done without occasioning the slightest incon- 
venience. 
Among the trading community, even if properly 'segregated,' there is, perhaps, 
a further chance of infection among those assistants whose duty requires their presence 
for a number of hours each day in those ' stores' or ' canteens ' of the factory at which 
the natives of the neighbourhood are retail customers. Here, a number of native 
women are continually passing in and out, staying often some minutes, with babies on 
their backs or children at their sides. These latter may be a source from which the 
otherwise uninfected Anopheles, usually so abundant in the shady parts of such ware- 
houses, may become infected, and hence some chance of European infection arise. 
But, in our opinion, such chances are extremely small — the period of each visit is 
short, everyone is usually on the move, and, altogether, the prospects of Anopheles 
obtaining a feed of blood from the few native children around, infinitesimally small. 
Such chances might, however, be negatived by individual precautions against the 
attacks of the insects by the assistants themselves. 
These illustrations of the conditions under which Europeans contract malarial 
fever in West Africa will also serve for many others than those mentioned. The 
government administrative commissioner, who visits many places where no Europeans 
dwell, has to rely on the native huts for his lodgment — and there is usually provided 
for him one in the midst of the native town. In a few days after his return to head- 
quarters he has an attack of fever contracted during his visit. 
Similarly the trading agent, in the interests of his firm, visits a native chief up 
country (the middleman) and elects to stay one or two days with him at his house in 
the midst of a crowd of native huts — or may be an assistant at the week end spends 
his Saturday afternoon and Sunday in a native town, with the result — an attack of 
fever some days afterwards. 
