221 
SUMMARY OF RESEARCHES ON NATIVE MALARIA 
AND MALARIAL PROPHYLAXIS ; ON BLACK- 
WATER FEVER : ITS NATURE AND 
PROPHYLAXIS* 
By J. W. W. STEPHENS, M.D., Cantab, D.P.H. 
LECTURER IN TROPICAL MEDICINE, LIVERPOOL 
AND 
S. R. CHRISTOPHERS, M.B., Vict., I. M.S. 
I 
OF our researches on malaria those relating to native malaria seem to us of such 
great practical importance that in the present report we have almost entirely 
confined ourselves to a discussion of these, and their application to the 
prevention of malaria among Europeans in the tropics. 
It is unnecessary here to discuss the question of the mosquito transmission ot 
malaria. We may, however, lay stress on some points which are as yet often over- 
looked. 
1. It is practically certain that the mosquito cycle is the only one. We 
cannot, in the space at our disposal, give all the reasons for this statement : suffice 
it to say that up to the present no competent observer has brought forward a single 
fact inexplicable by mosquito transmission or suggesting any other channel ot" 
infection. 
2. Regarding other hosts ot the malarial parasite than man, no one has 
found any other animal than man infected with the organism of human malaria. The 
supposition that monkeys may be the means of infecting Anopheles in the jungle is 
made highly improbable by Koch's researches. We may point out, too, that such a 
supposition is in no way needed to explain malaria contracted in the jungle, the real 
mode of infection in such conditions being now quite well understood. 
3. All recent research confirms the view that malaria is always derived from 
malaria pre-existing in others. It is as important to recognize that malaria is only 
derived from man as it is to appreciate that it is only transmitted by the mosquito 
{Anopheles). In other words, malaria is as much an infectious disease as scarlet fever, 
* Slightly modified from Papers Relating to the Investigation of Malaria and other Tropical Diseases, Colonial Office, 
June, 1903. A summary of all our researches will shortly be published as a Report to the Malarial Committee of the Royal Society, 
Harrison & Sons, London. 
