S. T. Darling 221 
This species has been introduced into America within historic times bv 
Kaffir slaves from Africa and to a certain extent by the East Indian coolies 
from Butish India and Java. It is the species most commonly found in 
America and has been spread from Virginia to Argentina. 
It is possible that either or both species have also been introduced into the 
American Continent from Asia, Indonesia or Polynesia by voyagers or storm- 
tossed fishermen. This is an enticing subject for future research. 
The American Continent may have been peopled (a) from Asia by way 
of Behring Straits, (6) from Asia or Indonesia across the Pacific, or (c) 1 from 
Polynesia across the Pacific. 
In the case of (a) cold would prevent the continuance of infection and the 
migrants would ainve free from hookworm, unless of course the average 
temperature of the Straits during migration was equal to that of North 
Carolina at the present time, for the latter temperature is the northern limit 
of autochthonous hookworm infection in America. In the case of (6) we might 
expect to find either or both A. duodenale and N. americanus among the 
' Amerinds or in such representatives of them as may have descended from (6). 
In the case of (c) we would expect to find only N. americanus. 
A survey of the species of hookworms harboured by Amerinds unexposed 
to infection from other sources, is urgently required to clear up some of these 
points. 
In Panama the population composed of Meztizos and Zambos was found 
to be almost exclusively infested with N. americanus which may have been 
derived in the first instance from Negroes. 
The reports of the Field Director of the International Health Board 
working in Central America show that the Indian (Amerind) population is 
infested with hookworms but the observations have been carried out in 
localities and among Indians who have been living in an environment con¬ 
taminated with excreta of Negroes and East Indians which contain embryos 
of both Necator and Agchylostoma. 
It will be necessary to search for tribes in inaccessible and remote places 
when it is desired to ascertain the primitive worm species index of uncon¬ 
taminated Indians (Amerinds). 
GEOGRAPHICAL AND RACIAL DISTRIBUTION OF HOOKWORMS. 
America. 
The species of hookworms encountered in the Southern States according 
to Dr Stiles is N . americanus , this was derived no doubt from the introduction 
of negro slaves from Africa. 
1 Cowan (1910), The Maoris of New Zealand Christchurch, N.Z., records that in 1909 a Chinese 
fishing junk picked up off the island of Chu San a party of three South Sea Islanders who were 
adrift in a canoe, they had mother of-pearl shell fish-hooks and other South Sea fishing tackle 
with them, and had been blown and drifted fully 2000 miles from a German possession in the 
Western Pacific. 
