S. T. Darling 
223 
Equatorial and South Africa. 
In a number of autopsies I performed in Johannesburg on Kaffirs from 
Mozambique, the only species encountered was N. americanus. 
Leiper, Looss and Fiilleborn found this species in South Africa and among 
Pygmies in the Cameroons, respectively. 
The Kaffirs 1 appear to be parasitized exclusively by this species. The 
introduction of slaves from Mozambique infested with Necator will account 
for the exclusive presence of this species in the Southern States of America. 
Asia—Indonesia. 
Malays. The natives of the Malay Peninsula. 
The Malays live in kampongs or native villages usually occupied solely 
by individuals of their own race. This was particularly true of the two 
kampongs near Kuala Lumpur where we obtained some data. 
Thirty-eight boys from Kampong Malacca yielded 2262 hookworms of 
which 2257 were N. americanus, and 5 were ancylostomes, 3 A. duodenale and 
2 A. ceylanicum. 
In Ulu Gombak 39 boys yielded 1559 hookworms, 1546 of these were 
N. americanus and 13 ancylostomes, of these 7 were A. duodenale and 6 
A. ceylanicum. 
Thus the percentage of ancylostomes present in the Malay kampong boys 
was 0*22 and 0-8 respectively. 
Taking the two groups of 77 boys as a whole as representative of what 
the Malay worm formula should be and considering Necator and A. duodenale 
only, there were 3813 worms of which 10 only were A. duodenale, or an 
A. duodenale index or percentage of 0-26. 
Adult Malays. Adults from their occupations are often brought into 
contact with Chinese of which there are large numbers in the peninsula and 
they have more opportunities for becoming infested with the hookworms of 
the Chinese, who, as it will be shown, harbour very large numbers of A. duo¬ 
denale. We may expect the adult Malays to-day therefore to show some 
evidences of contamination from Chinese sources. 
Sixteen adult Malays were found to harbour 1138 hookworms of which 
10 were A. duodenale and the remainder N. americanus, the A. duodenale 
index being 0-9. Thus we see that the autochthonous Malay population of 
the Malay Peninsula harbours nearly a pure culture of N. americanus. 
Malays of the Island of Java. 
Among the natives of Java there was encountered a very distinct difference 
between the ancylostome index of the people of West Java and that of people 
A. duodenale unquestionably is a more malignant hookworm than Necator. It is possible 
that some of the alleged immunity of the negro to the effects of hookworm infection is clue to the 
fact that Kaffirs and their descendants are very largely parasitized by Necator and not by A. duo¬ 
denale. 
Parasitology xn i - 
