If the water is not filtered, it should be boiled for thirty minutes. The water should be run off in the morning, then poured into a well-kept tea-kettle and boiled. It is then allowed to stand and become partially cooled in covered vessels, when it is poured into large bottles—quarts are the most convenient size; these should be stoppered with corks of absorbent cotton. When cool, the bottles are placed in the refrigerator beside the ice. Water should be boiled every morning for the twenty-four hours. Boiling for this length of time secures the destruction of all the germs of disease, and it is doubly essential on the return to town in the fall, when the house has been closed for some time; also when typhoid fever in the neighborhood indicates the strong possibility of the impurity of the water-supply. The mistake should not be made of undoing the good that has been done by boiling the water by the addition of ice to the water when it is placed on the table. Furthermore, ice-water is so cold that it retards and interferes with the digestive processes. In the internal use of water the same marked difference is caused by the different temperatures at which the water is taken, as was seen in the external applications of water; but, while the temperature of the skin is about 90° F., that of the mucous membrane lining the digestive tract is 98.6° F. and above. _The Action of the Internal Use of Water on the Heart and Blood._—Water improves the quality of the blood, both by its direct action on the constituents and by the increased elimination of waste-products. By the increase of the volume of blood, a more energetic contraction of the heart is caused, and the activity of all the glands of the body is increased. There is a greater amount of oxygen absorbed by the lungs; oxidation in the tissues is carried on more perfectly, the result of which is that there is a diminution or absence of the products of incomplete combustion in the body, such as uric acid, the oxalates, etc. By the increase of the blood-pressure, caused by drinking water in sufficient quantities, the activity of the kidneys is increased, and this not only in the amount of urine passed, but also of the solid constituents, which are the waste-products, removed from the body through the agency of the kidneys.