427 ON CORAL REEFS AS A CAUSE OF FEVER* 
make us believe Edam did in 1800, and those islands being 
destitute of adjacent exposed coral reefs, the inhabitants were 
free from fever or only subject to slight intermittent fevers 
when their houses were built close to a marsh. 
I am moreover informed that there are other islands in 
Batavia harbour as bad as Onrust, and little inferior to Edam 
in the virulence of the fever, where positively no marshes 
exist, the only vegetation being a kind of scrub, and a few 
high trees. In this list is Kuypers island and Purmerent, on 
the latter of which an hospital was once built and was in 
existence when Captain Cook visited Batavia, but from the 
unhealtbiness of the place has since been removed to Wel- 
treveden 3 miles inland from Batavia. 
It is evident that at the time Mr Wade Shields made his 
report only 2 causes of fever could suggest themselves to the 
minds of the medical men. The first cause was the exhalation 
of miasm from the precincts of Batavia and the adjacent mud 
flats, the second was marshes, stagnant marshes on the is¬ 
lands themselves, from every foot o! which pestilential vapours 
were supposed to emanate. The first cause was clearly proved 
by the medical men at the time not the exciting cause of the 
endemic; nothing was therefore left, but to fall back upon 
the second, and it was consequently elevated to the honour. 
This and the other being the only two probable causes of the 
endemic fever of the island and harbour of Batavia, having 
been considered and found not sufficient, I would now propose 
my theory, as a sufficient, clear, and satisfactory explanation 
of the cause of the endemic remittent and of the intermittent 
fevers of the harbour ot Batavia, (.Journ. Ind. Arch. vol. II p. 
599.) “That whenever a coral reef is exposed at low water, 
animal decomposition will go on to an extent proportioned to 
the size of the reef, caet par., and that malaria will be the 
result of this decomposition, which is one and the principal 
cause of the fevers endemic in such localities .’* 
According to charts, and the authority of many individuals 
of great experience, the islands of Onrust, Kuypers, Purme- 
rent, Edam and others, are surrounded by coral reefs more or 
less exposed at low water. 
Here ll ten is the cause of the endemic fever, which, according 
to t ap'ain Cook, in his time swept away by death half of the 
crews ot vessels that, annually arrived from Europe, and com¬ 
mitted fearful ravages amongst his own officers and sailors 
who had so successfully encountered every hardship and dis¬ 
tress in their voyage round the world,—a fever that has not 
yielded its sway to all the skill and science of man, and has 
baffled all human contrivances for its amelioration,—a fever 
