218 Distribution of Hookworms 
expelled from the autochthones in the countries in question discloses some 
interesting facts. 
Taking the island of Viti Levu, the autochthones show almost a pure in¬ 
fection with one species of worm, Necator americanus. No specimens of 
Agchylostoma duodenale were encountered in Fijians except among those that 
had lived in towns, or near plantations occupied by East Indians. 
Among indentured East Indian coolies from Calcutta 21-4 % of the worms 
expelled were A. duodenale, the rest were N. americanus. 
Wherever Fijians were living near East Indians, they were found to have 
become infected with A. duodenale , derived from the latter race. 
Infection by A. duodenale is becoming widespread among town-dwelling 
Fijians. 
After East Indians have lived in Fiji for 10 to 15 years or more they lose 
a good many of their A. duodenale and disclose a relatively larger proportion 
of N. americanus. 
In Malaya the Malays were found to harbour nearly a pure culture of 
N. americanus, for 98*99 % of their worms were of this species, the remainder 
being A. duodenale and A. ceylanicum. This may be considered the formula 
of the country. Chinese coolies coming in to Malaya bring a worm formula 
of 35 to 85 % A. duodenale, the remainder being N. americanus. However, 
among the generation of Chinese born in Malaya—Straits born Chinese, who 
have often taken up Malay customs—eating with their fingers, etc., and who 
may have dropped Chinese customs and associates to a greater or less extent, 
it was remarkable to find that they had dropped also the Chinese worm 
formula as well, and taken up one like that of the people of the country. At 
the same time the influx of Chinese coolies with their large ancylostome index 
is gradually adding an increasing number of hookworms of this species to 
the common species of the natives of the peninsula. 
The effect of migration into a country whose people have a different index 
from that of the immigrants, is to make the immigrant take on the worm 
index of the autochthones, while the index of the latter is more or less modified 
by the implantation of the worm species of the immigrant. 
This was very clearly shown in Fiji. 
The autochthonous population as represented by the people of Nasoqo, 
a remote and inaccessible interior mountain village, were found to be infected 
with N. americanus (six specimens of A. ceylanicum were encountered). Not 
a single specimen of A. duodenale was taken. The ancylostome index of the 
autochthones then must be considered as nil. 
In the villages near Nausori where the autochthones are exposed to infection 
from soil polluted by East Indians, they were found to be harbouring some 
A. duodenale. Thus ten Fijians treated, were found to have 1309 hookworms 
of which 1246 were N. americanus and 63 A. duodenale (there were six dog- 
worms A. ceylanicum ). 
The ancylostome index of these town-dwelling Fijians was 4*8 % and 
