316 On Malaria. 
as has has already been shewn, are productive of disease ; and this 
sufficiently accounts for the distresses often suffered by the pioneers 
in new settlements, while the disappearance of those endemic mala- 
dies after the country has changed its aspect by cultivation, proves 
that we have not mistaken the cause.* 
Another source of malaria remarked by Dr. McCulloch, is bilge 
water, to which he charges a great proportion of the sickness expe- 
rienced on shipboard since the disappearance of the scurvy. It is 
his opinion, that the noxious effluvia are generated in hot climates by 
the action of the bilge water upon the wood of the ship itself, often 
augmented by corn, coffee and sugar cargoes, and sometimes by the 
quality of the ballast. It is notorious that grain and sugar, by sifting 
through the seams, render the bilge water excessively offensive, and 
Dr. McCulloch instances the most destructive fevers, proceeding 
from that cause.. Gravel and mud ballast are also conducive to simi- 
lar results, while iron ballast is safe. The simple and easy remedies 
for this evil are ventilation, and washing the ship every day by the 
plug, until the water drawn by the pumps is as clear, as that in the 
sea outside of the ship. A most thorough attention to ventilating the 
hold is also essential, because there is the origin and residence of the 
evil. The efficacy of this practice has been tested by experiment 
in the British naval and merchant service.+ Another exposure of 
ships to this class of diseases, is from communication with the har- 
bors and shores of tropical climates. Although it is not practicable 
to bring this set of dangers under as positive regulations as the for- 
mer, yet great perils may be avoided, which are now thoughtlessly or 
ignorantly incurred by ships’ compunies in tropical regions. It 
been ascertained that malaria has been distinctly propagated to 2 
ship at anchor, five miles distant, and that a fatal cholera occurred 
instantly three miles from the land, upon a shift of wind.{ It is there- 
fore Sere desirable that ships should not approach such shores 
_ *“Thelong fever, one form of the bilious remittent, is nearly extinct in the 
atime states, although eighty years ago, it was one of the most terrible diseases: sae 
this cl te. Where the country has been = h one hundred and fifty years, the 
ter, wegltepapadeal *_-Webster on Pestilence 
1 From what is known of the astonishing ease of chlorine in oincas 
: it is not too much to hope, Bae it may prove an efficient auxiliary in extingy uishin 
of counteracting the meet sieves sect perhaps even of superseding the necessity 
altho never be substituted for thorough clean- 
y McCulloch on Malaria on shipboard. 
