ON CORAL REEFS AS A CAUSE OF FEVER, 126 
66 the pestilential miasmata in a concentrated form issuing 
from every foot of ground.’ 5 In receiving this statement 
of Mr Wade Shields, it must be borne in mind that 
the island itself is not more than a quarter of a mile in 
diameter, and therefore if it was one entire marsh of the 
most stagnant kind, I am convinced, from the examina¬ 
tion of analogous places, it could not produce such an ende¬ 
mic fever. Whatever it was in 1800, thirty years afterwards it 
was much changed, as appears from Mr Riley’s account of it 
'‘it is in form and appearance like a hump, and therefore may 
be concluded to have no marshes. It is covered by the scrub 
and trees usual on small islands in the Straits/* Mr Leisk, 
Marine Surveyor, Singapore, and long a resident in Java, 
speaks more decidedly as to its nature “it is” says he” a low 
coral island about a quarter of a mile in diameter, surrounded 
by a coral reef with a detached coral patch to the northward of 
it; (I am not certain whether this patch is ever dry)—the island 
is covered with trees and bushes but I never saw a swamp on 
it; it appeared to me to be dry, the soil consisting of a mix¬ 
ture of coral, other stones and coral sand. I have been on it 
twice but never found any disagreable smell, more than on any 
other coral island/’ 
From the many inquiries that I have made of those who have 
frequented this port, I cannot learn that the island has undergone 
any change for a series of years, except that trees have been 
cut down and thereby a more favourable state produced for 
generating miasm than in 1800, when the high trees prevented 
the full action of the sun’s rays. Rut allowing that formerly 
there was a marsh—and that now (as we positively know) 
there is none, yet the disappearance of the marsh has not 
improved the climate of the island, for to this day whoever 
sleeps on shore or exposes himself to the influence of the 
winds from the island, as surely is attacked by fever as those 
who were cut off in 1800. If absence of vegetation and 
marshes ensured immunity from fever, why was and is not 
Onrust free, as it was then and now is like a well cleared 
and beautifully laid out garden ? Yet is its fever very little 
inferior in intensity to that of Edam. In many parts of the 
globe, amongst the Nicobars, the Maldives and in the island 
of Ascension there are no marshes, yet are the inhabitants 
more or less afflicted with fever, showing that the island of 
Edam is not singular in its freedom from marshes but not of 
fever. In and near the Straits of Singapore a few degrees 
only removed from Batavia, but still under the same tropical 
influences, are many ^islands, which present appearances in 
vegetation exactly similar to what Mr Wade Shields would 
