On Malaria. 309 
lence of its effects as we advance towards warmer and tropical cli- 
mates. ‘The degree of heat in Calcutta, during the prevalence of 
malignant intermittents was from 86° to 76°, Fahr. In Syria it was 
86°, and increasing.* At Bassora in 1780, previous to a most fright- 
ful and malignant intermittent, the thermometer rose from 115° to 
156° in the shade.t On Long Island 1828, in August, just before 
the remitting fever became epidemic, it was from 91° to 73°. 
But in temperate climates it is not during the actual presence of 
the heat that the pestilential power is most injurious. The Italian 
peasant takes a siesta upon the ground at noon and escapes unhurt.§ 
The poisonous gases and vapors at that hour, are so rarefied, or diffu- 
sed, or in common phrase, so dried up, that they are harmless; but 
when the air is cooled sufficiently to condense the aqueous vapors, and 
they descend in dews, imparting a delightful freshness, then it is that 
the insidious and baneful poison is abroad. Those peasants “to whom 
the earth serves as a bed, after the cold dews have descended upon it, 
and who pass the night on the moist turf,’ seldom, if ever, escape; 
and laborers who: incautiously sit upon the ground, are sometimes 
struck with apoplexy, or even with death. On this principle it is 
easy to see, why the diseases proceeding from aes pininey Ste 
aggravated in autumn. During the summer, 
ous, except in the site and morning; but the age of of summer having 
* Bancroft on fevers. t Tytler on plague. a faz! 
- t 1am indebted to Mr. Kellogg, Principal of the Academ. ikaie 
bush, Long Island, for the following accurate table, which pas — peitesde S heat 
and drought in eliciting and concentrating malaria in our own climate. * 
the amount of rain which fell in June, July, and August, and the summer temper 
ature of four consecutive years 
ey 
Rain gues the months of ie ea teens 
June, July, August. ‘ : Se 
Years. In. In. In. Total 
1826. 8.60 3.79 7.95 20.32 
1827 3.68 3.58 5.47 12.73 
1828285) B98 1.97 38 Andnone after the oneriedires 
1829. 3.38 2.35 4.84 10.5 es 
Sins 
June, July, "August. 
Highest. Mean. Highest. Mean. Highest. Mean. 
1826." gi. 89. 89. 71.90 
1827.86: 65.80 94, © 72.10 96. . 70.51 
1828 84. “ . 91. 71.88 91. . 78.45 
1829 87. 70.65 
85. 
§ Chateauvieux’s gee Travels. 
