128 Dr Stephens, The Prevention of Malaria. 
Table III. 
House 
Bing forms 
Pigmented 
leucocytes 
Crescents 
Total infected 
children 
Total children 
examined 
1 
1 
2 
2 
4 
2 
No children 
3 
1 
1 
1 
4 
1 
2 
3 
4 
5 
5 
1 
1 
1 
6 
2 
2 
3 
7 
One child only 
1 
8 
1 
1 
1 
9 
No children 
10 
No children 
Total ... 
6 
8 
11 
16 
We have briefly described the distribution of Anopheles in some 
typical malarial parts of W. Africa and also the conditions which 
determine the existence of breeding grounds. A conception of 
these conditions is necessary before undertaking any measures for 
the destruction of Anopheles or their breeding grounds; but an 
actual knowledge of the places can only afford a really adequate 
idea of the conditions, and it is a want of complete knowledge on 
these points that has led to many immature schemes for wholesale 
destruction of mosquitoes and to an unrealised predicted freedom 
from malaria. But as we have already pointed out it is not 
so much the question of distribution of Anopheles that is important 
as the absolutely fundamental question, what is the source of the 
infection of Anopheles and how can Europeans protect themselves 
from infection ? 
Before this work on native children was done, it had been 
thought that the source of infection was the European conva- 
lescent from an attack of fever ; for it is in this state that gametes 
usually occur (we shall point out later however that as a matter of 
fact in W. Africa they rarely do occur). But it was always 
difficult to understand how the same mosquitoes which had got 
infected from such (supposed infective) cases should again find out 
