450 Proceedings of the Royal Physical Society. 
Nyanza, bounded between 32° and 38° E. long., where the 
mean variation is from 10° to 20° F. The mean annual 
rainfall is about 50 inches, except in the centre of this area, 
where it reaches about 100 inches, this including the Congo 
forest district and the country to the west of Tanganyika as 
far south as 10° S. lat. In this district also the relative 
humidity is over 70 per cent., but over the whole district the 
relative humidity may be taken as about 66 to 68 per cent. 
The whole region is highly malarious, but I will give a 
brief account of malaria as I met with it in Central Africa. 
The area referred to extends from Khartoum in the north as 
far south as the Victoria and Albert Lakes, and also includes 
the Rohl and Bahr-el-Ghazel districts, The distribution of 
malaria in this region is unequal, and the topography of the 
country exerts an influence both upon its frequency and its 
severity. In low-lying swampy regions malaria is very 
common, the natives suffering to a considerable extent from 
mild attacks of intermittent fever. Occasionally one sees a 
case of well-marked remittent, but perhaps the most fre- 
quent variety met with is a form which at first sight appears 
to be a continued fever lasting from five to seven days. But 
when these fevers are examined carefully it is found that 
they are really either mild remittent (for there are distinct 
remissions, which, however, must_be carefully looked for) or 
they are quotidian, with badly-marked paroxysms. A very 
brief cold stage occurs daily, then follow eighteen or twenty 
hours of hot stage with a temperature of 102°-103° F., 
followed by an hour or so of apyrexia after a very slight 
perspiration. Throughout the whole region the natives, who 
are fairly stationary in one district, suffer comparatively 
little, and from but slight attacks of intermittent fever, but 
if removed to a new locality they suffer from much more 
severe attacks, from remittent fever for the most part, and it 
is a noteworthy fact that after slave raiding or war numbers 
of men are struck down by severe forms of fever. 
In the higher regions the fevers become more rare until 
one reaches districts having an altitude of from 3000 to 4000 
feet, where they almost entirely disappear. A good example 
of this may be seen in the country to the north-west of the 
