V.

It has been observed by medical men, from the time of Hippocrates down to the present day, that the effects of a heated atmosphere, saturated with moisture, are very injurious, and exceedingly prolific of disease.

Air at 32 deg. of Fahrenheit, according to Leslie, contains, when saturated with moisture, 1/160 of its weight of water; at 59 deg., 1/80; at 86 deg., 1/40; at 113 deg., 1/20; its capacity for moisture being doubled by each increase of 27 deg. of Fahrenheit.

The degree of heat within the stockade sometimes rose to beyond 110 deg. Fahrenheit, and the degree of humidity was correspondingly as great. That moisture exerts more influence in the production of disease than any other meteorological condition, is well observed in every-day life. M. Bossi found, in his investigations, that the extreme and constant humidity of the atmosphere affected the barometer of health very markedly, and he established the following ratio of mortality for the different regions: The ratio for mountains and elevated regions he observed to be one in thirty-eight; on the banks of rivers, one in twenty-six; on the level plains, sown with grain, one in twenty-four, and in parts interspersed with pools and marshes, one in twenty.