425 ON CORAL REEFS AS A CAUSE OF FEVER. 
and the surgeon, who both died of the fever, both having 
slept on the island. Not only did all the crew escape, but 25 
men of the detachment from the 12th Regiment (whose com¬ 
rades suffered so much) shared the same immunity. H. M. 
S. Bravre which was anchored at a greater distance from Ba¬ 
tavia but under the lee of the island of Onrust lost nearly half 
her crew, and more than half the soldiers embarked in her. 
A third reason , and a most convincing one, that the ende¬ 
mic of the islands and the shipping arises from a different 
cause from that of the endemic of the town of Batavia, is 
that in some years the fever is severe and virulent amongst 
the shipping, and not unusually so in Batavia, but still more 
frequently it has been severe in the town of Batavia and not 
felt in the shipping. Now such predispoing causes, as changes 
in the state of the atmosphere involving changes in its tempe¬ 
rature, moisture, and electric state equally affect the town, and 
shipping; if then the fever is not simultaneous in these 
places, there must be two different exciting causes, otherwise 
the malaria from the mud banks and rivers &c- when it gives 
rise to an epidemic in the town, would do the same in the 
shipping. 
Since the Endemic fever of the islands cannot be supposed 
to arise from the malaria generated on the mainland, we must 
examine the second cause assigned, or the nature of the soil 
on the islands. 
Mr Wade Shields in his report, having been convinced by 
bis experience of Edam that the fever did not arise from sour- 
ces so far distant as the mainland, falls back on the islands 
themselves for a cause. 
“ Onrust is a small island three miles from the main, well 
cleared of trees, underwood and jungle, nearly flat and free 
from swamps and marshes, except one very small spot, which 
however is daily covered twice by the tides/’ To this favou¬ 
rable condition of the island he attributes the less deadly cha¬ 
racter of its fever compared with that of Edam ; but what should 
give rise to that fever, less deadly though it be ? He further 
adds, from the fetid exhalations which were conveyed by the 
land winds from the neighbourhood of Batavia, the sick were 
easily secured, by closing certain apertures in their apart¬ 
ments till the sun dispersed the vapours in the morning, after 
which there did not appear to be any clanger from the Mias¬ 
mata disengaged during the day. Passing on to Edam he 
accounts for the greater virulence of the endemic there, “by 
its being covered with trees, long grass and jungle, leaving 
a part ot the island itself in a stagnant marshy state’’, and, 
warming as he proceeds, he describes as if he had seen— 
