224 
Distribution of Hookworms 
living east of the Tji Manoek river, this difference corresponds with a difference 
in the ethnic stocks in the two regions. 
Worm counts were carried out among Malays in four kampongs in the 
city of Batavia (West Java): a total of 2935 hookworms were obtained from 
92 people of which only 26 were A. duodenale, the remainder being N. ameri- 
canus ; the percentage of ancylostomes therefore was 0-88 a figure corresponding 
closely with that of the Malays of the Malay Peninsula. 
In the mountainous region of the Preanger (West Java) there was an 
absence of A. duodenale which was very striking indeed. 
Twenty-five Malays (Sudanese) in the dessa or village of Endil Tjhoeavg- 
laagte were found to be harbouring 1275 hookworms, and of these two were 
A. ceylanicum (derived from dogs), the rest being N. americanus. 
In the dessa of Tjimatjam, at an elevation of 3600 feet, near the volcano 
Gedeh, where there was a minimum pollution of soil and of the water courses, 
25 persons yielded only 150 hookworms all N. americanus. 
In these two dessas in the Preanger the A. duodenale index was nil. 
This absence of A. duodenale among 50 representative Malays in the 
Preanger, indicates in the most striking way that the hookworm common 
and proper to the people of West Java is N. americanus and that A. duodenale 
when found represents an extraneous infestation from some alien source. 
Wishing to include in the survey some of the people of mid-Java I visited 
two villages near Cheribon on the North Shore: 
At Gebongelir, 50 Javanese were treated, and a total of 2339 hookworms 
were obtained from them; of these 308 were A. duodenale the remainder being 
N. americanus , the ancylostome index being 13-1. 
At Kalimaro, a village near by, 5140 hookworms were obtained from 
24 persons; 332 were A. duodenale and the remainder were N. americanus , 
an ancylostome index of 6-2. 
In the dessa of Kebasekan near Keboemen, not far from Djokjakarta 
(mid-Java), 25 persons yielded 4082 hookworms, the percentage of A. duo¬ 
denale being 5-4. 
From Krakal and Karangsari, villages in the same district, 28 Javanese 
yielded 10,861 hookworms of which 770 were A. duodenale ; the ancylostome 
index being 7-0 %. 
The distribution of A. duodenale and N. americanus in Java and the 
neighbouring islands is well displayed in an analysis of the results of the 
- worm findings among the prisoners in the jail in Batavia. 
In this jail there are no opportunities for acquiring new hookworm in¬ 
festation. Food is dispensed in a pasteurized or sterilized state while still warm. 
The sanitary arrangements while primitive I think effectually prevent hook¬ 
worm infestation. 
Confirmatory of this is the fact that of 118 men treated who had been in the 
jail for periods up to seven years or more, the average number per man was 
found to diminish with each succeeding year of imprisonment. This is inter- 
