Let us review these three great principles of destruction, as laid down by the distinguished European authority, and apply them in the explanations of the mortality at Andersonville. 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° of Fahrenheit, according to Leslie, contains, when saturated with moisture, 1/160 of its weight of water; at 59°, 1/80; at 86°, 1/40; at 113°, 1/20; its capacity for moisture being doubled by each increase of 27° of Fahrenheit. The degree of heat within the stockade sometimes rose to beyond 110° 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. VI. The influence and value of pure and healthy air may be seen in the simplest physiological observations. Animal life is fed and sustained by respiration, as well as vegetable life. It is from the blood that animal life derives the materials and forces which maintain it, and we have seen how this owes its vivifying properties, in a great measure, to the oxygen which it receives from the respiratory organs, and how its power is in direct ratio to the purity of the air breathed. A vitiated atmosphere manifests itself at once in the nutritive powers of the vital stream; and the more feeble the respiration, the less rich the blood. This "oxygen enters by the lungs into the blood, and with the blood flows on and circulates through the body; it also enters partly into the composition of the tissues, so that it is a real food, and it is as necessary to the construction of the human body as the other forms of food which are usually introduced into the stomach." The weight of oxygen, says Professor Johnston, taken up by the lungs, exceeds considerably that of all the dry, solid food which is introduced into the stomach of a healthy man.