SIXTH PAPER.
PREVALENCE—METEOROLOGY.
The relations existing between meteorological conditions and pneumonic fever are of the most interesting nature, and many and various are the rules and laws relating thereto that have been formulated by systematic writers, but the exceptions to them are so numerous and important that they are greatly weakened or rendered entirely nugatory.
It may be affirmed, as a general proposition, ¹ that pneumonic fever will be found to prevail to a greater extent than ordinarily, the influence of season and epidemics excepted, when the daily range of temperature, ² humidity of the atmosphere, ³ velocity of the wind, range of barometer, amount of atmospheric pressure" and amount of ozone present in the air are greater than the average, and that it will be less prevalent when opposite conditions prevail. Again, it will be found that an excess of cases will be met with when the range of