V. THE PREVENTION OF MALARIAL FEVER 
At the commencement of this chapter, which will treat of the methods to be 
adopted for the prevention of malarial fever, the members of the expedition wish very 
strongly to indicate that the suggestions given are based on their own experiences 
and observations, and, as other scientific workers have as a result of their researches 
in other parts of the world suggested somewhat different lines of procedure with the 
same object in view, we consider the recommendations hereafter suggested as the most 
suitable, in tact the only possible, if malarial fever in the country of Nigeria is to be 
successfully combated. Whether they can be satisfactorily adopted in other parts of 
West Africa we are not, from personal observation, able to say, but it is noteworthy 
that the members of the only other malaria expedition which has made a long stay on 
the Coast — namely, the Royal Society's Commission in the districts of Sierra Leone, 
Accra, and Lagos, have recommended absolutely the same methods. 
With a view as to the possibility of preventing malarial fever, it is to be noted 
that during the life history of the malarial parasite in the bodies of its two hosts — 
man and the mosquito {Anopheles) — the parasite may be attacked or avoided, 
A in its intermediary host — man, 
(i) during the incubation period of the disease ; and 
(ii) during the course of the disease. 
B in its definitive host — the mosquito of the genus Anopheles by 
(i) preventing inoculation, that is, their bites ; 
(ii) the destruction of the insect in any of its stages of development — 
as ovum, larva, or adult. 
A. The only means of attacking the parasite during its life history in the 
intermediary host — man — at present known is by the action of quinine, either as a 
prophylactic during the incubation period of the disease, or as a curative measure 
during the course of the disease. 
Professor Koch, as a result of his researches in the East Indies, has 
recommended the wholesale administration of quinine to Europeans and natives as 
the most practical method for the prevention of malarial fever in those parts. How- 
ever practicable it may appear as a preventive measure in the parts visited by him, it 
is absolutely impracticable in West Africa. Manson 1 also suggested this as one of a 
number of methods for adoption throughout West Africa. There are a number of 
conditions which strongly militate against such a course of procedure. It has been 
shewn in a previous chapter that a large percentage of native children under ten 
