'202 DR. s. H. LONG ON THE MOSQUITO-MALARIA THEORY. 
Professor Koch, viz., the searching out of all cases of Malaria and 
rendering these harmless by curing them with quinine. By this 
means he was able to greatly reduce Malaria in the on-coming 
season at Stephansort. In his fifth report to the German Imperial 
Health Bureau, Koch sums up as follows : “ The results of our 
experiment, which has lasted nearly six months, have been so 
uniform and unequivocal that they cannot he regarded as accidental. 
We may assume that it is directly owing to the measures we have 
adopted that Malaria here has, in a comparatively short time, almost 
disappeared.” 
Such a method as this can obviously only be successfully adopted 
in a community which can he kept under observation, and is, there- 
fore, not applicable to Africa. 
In Africa, however, the second method is peculiarly adaptable. 
(2) The segregation of Europeans from Natives. This method 
was primarily recommended by the Malaria Commission, and later, 
strongly adopted by the Liverpool School of Tropical Medicine 
Expedition to Nigeria. 
This method is the outcome of observation upon the blood of 
native children. In New Guinea, Koch found that in nearly 
100 per cent, of the native children examined, the parasite of 
infection was present. He also showed that with the advancement 
of age, immunity was produced, so that in the case of adults immunity 
was present, and the source of the infection was absent. Similar 
results were independently arrived at by the Malaria Commission 
amongst the native children of tropical Africa. In a paper on the 
“Prevention of Malaria” (Thompson Yates’ Laboratories Report, 
vol. iii. part 2, p. 174), Dr. Christopher says: “ With a knowledge 
of the ubiquity of native Malaria, the method of infection of 
Europeans becomes abundantly clear. The reputed unhealthiness 
or healthiness of stations is seen at once to be dependent on the 
proximity or non-proximity of native huts. The attack of Malaria 
after a tour up country, the Malaria at military stations like Prah-su, 
the abundance of Malaria on railways, are all explicable when the 
extraordinary condition of universal native infection is appreciated. 
It is evident that could Europeans avoid the close proximity of 
native huts they would do away with a very obvious and great 
source of infection. That they could avoid the neighbourhood of 
huts, no one who has studied the condition of life in Africa can 
doubt.” 
