314 On Malaria. 
The lands are productive and assiduously cultivated. Salt marshes 
occur on the sea shores frequently, and on the margins of small bays, 
which indent the coast. In June and July of 1828, the fall of rain 
was not far from the average of preceding summers, but much of it 
fell in showers, and the rapid alternations of rain and sunshine were 
followed by very luxuriant vegetation. In August, a little more than 
an inch of rain fell before the 5th, and to this succeeded a drought for 
the remainder of the month. The mean heat of the month was 73° 
45’, though it was occasionally as high as 91° Fahr. The margins 
of ponds were soon laid bare, the rank and macerated herbage was 
every were exposed to the unclouded rays of the sun, and the salt 
marshes yielded their co-operation. Various forces one to in- 
crease the energy and extent of pestiferous influences. or example, 
the greater amount of surface and materials exposed, gave out a larger 
quantity of poison, and that more concentrated ; the mitigating effect 
of rain was also needed to absorb or dilute the miasmata, or, by keep- 
ing the ponds full, to secure the surfaces and materials usually under 
water, ‘from the chemical action of heat. Whether this theory is or 
is not correct, the event was, that in this month a remitting bilious 
fever endemic in many villages, became rapidly and extensively 
epidemic, including all the open country ; sudden attacks seized the 
_ most healthy, and those who in the spring had been affected with 
fever and ague, found their relapses of a malignant character ; and 
great mortality ensued. On the western verge of this tract is situ- 
ated a town containing ten thousand inhabitants, and although the 
epidemic ¢ came > almost to p the doors; aa the sick were in every house, 
and t half a mile distant, 
yet not a walls eave ‘coctared 3 in the town, excepting a few persons 
who had been in the country, and who after their return were visited 
with fever. The site of the town is on table land about eighty feet 
above the level of the sea, but not high enough to secure it from the 
winds blowing over the adjacent country. It seems probable that it 
owed its safety to the fires, smoke, and other counteracting, 
unknown causes, which eee meeeevlis aw) we a ane tAOE = 
f of the truth of the positi roar 
extinguish 5 the malarious prineiple, and another reason for suppoS~ 
< in - Aperpat toa vegetable origin. But if malaria is subdued by 
: og Sof a sage arises, why do complaints proceeding from it ¢- 
in winter? To this j inquiry, Dr. Keate’s report of those regi- 
